Download: http://wordpress.org/extend/plugins/default-thumbnail-plus

Thumbnail Selection Hierarchy

The hierarchy below determines what thumbnail will be chosen, in other words the plugin first checks if the user has manually set a featured image. If not then it checks if it has a custom field containing an attachment id, and so on. Once the plugin gets to the last step if no default thumbnail image is set then no post thumbnail will be displayed.

1. Featured Image
2. Custom Field
3. Image Attachment
4. Embedded image
5. Embedded video
6. Category/Tag/Taxonomy Thumbnail
7. Default Thumbnail

Add Filter (Category/Tag/Taxonomy Thumbnail)

You can add filters which allow you to select a thumbnail for a specific category, tag, or custom taxonomy. The value field is required and must contain either a comma separated list of slug, id, or title for a existing category, tag, or custom taxonomy. Any post that does not have a post-thumbnail set and has the specified tag, or is a member of the category or taxonomy will show the default thumbnail specified.

Use image attachment if available

Automatically use the post’s first available image attachment for the thumbnail. This is useful for older posts that haven’t got a featured image set.

Custom Field

Enter a custom field key here, it’s value if set will become the default post thumbnail for that post. The custom field value can either be an Attachment ID, or a link to an image.

Note: If the custom field value contains a link to an image it will output a simple image tag and attempt to populate the width and height attributes. However the aspect ratio may not match other thumbnails. The plugin does not check if the image exists or is of valid type or size.

Use embedded image if available

Automatically use the post’s first available embedded image for the thumbnail. This is useful if you embed external images.

Note: This option does not work with has_post_thumbnail() or get_post_thumbnail_id(). If the “cache external images” option is set then the plugin will automatically resize, crop the image and store a local copy.

Use embedded video if available

Automatically use the post’s first available embedded video for the thumbnail (YouTube only).

Note: This option does not work with has_post_thumbnail() or get_post_thumbnail_id(). If the “cache external images” option is set then the plugin will automatically resize, crop the image and store a local copy.

Excluded posts

List of posts to be ignored by this plugin. Comma separated e.g. 10, 2, 7, 14.

Note: These posts may still display a thumbnail if one has been set manually (using the “Set featured image” button on the post page).

Functions

The following functions work to directly return post thumbnail even if the plugin hooks have been disabled. This allows you to disable the filters and call the plugin manually. This should only be used if you are creating a custom theme and can ensure that DefaultThumbnailPlus is installed.

dpt_post_thumbnail_id($post_id, $size = null, $attr = ”)
Returns the post thumbnail ID. Doesn’t work with embedded images.

dpt_post_thumbnail_html($post_id, $size = null, $attr = ”)
Directly calls the default post thumbnail function. Works the same as calling get_the_post_thumbnail().

dpt_post_thumbnail_src($post_id, $size = null)
Returns href to post thumbnail image.

Why can’t I see any thumbnails with my custom theme?

A number of themes use has_post_thumbnail() to check if a post thumbnail exists before calling the_post_thumbnail() to display the thumbnail. The problem with this is that thumbnails that are linked to directly (either external images or video thumbnails) won’t return correctly for this check and therefore may not show.
 
To fix this issue you will need to look for the following code in your theme:

if(has_post_thumbnail()) {
    the_post_thumbnail(...);
}

 
And simply remove the call to has_post_thumbnail() so you are left with this:

the_post_thumbnail(...);

TwentyEleven

The header only works with image attachments, i.e. embedded images/video thumbnails won’t show.

The header attachment width also has to be greater than the custom-header width option (default 1000px). This is generally a good thing though since it prevents low resolution images from displaying in the header.

WooThemes

WooThemes call a function called woo_image() rather than using the default WordPress functionality. This causes the default post thumbnail to never show.

So to fix this you need to override the woo_image() function with a custom implementation that reverts to using WordPress’s in-built functions. To do this paste the following code into the TOP of the themes functions.php file found in /wp-content/themes/your_themes_name after the opening <?php tag.

//Override the default woothemes image function and revert to using the default wordpress function.
if ( ! is_admin() && ! function_exists('woo_image')){
    function woo_image($args) {
        global $post;

        $size = null;
        $attr = array();
        $before = '';
        $after = '';
        $class = '';

        if ( !is_array($args) )
            parse_str( $args, $args );

        extract($args);

        if(empty($id))
            $id = $post->ID;

        if(isset($width) && isset($height))
            $size = array($width, $height);

        $attr['class'] = 'woo-image '.$class;

        if(isset($alt))
            $attr['alt'] = $alt;

        $output = $before . get_the_post_thumbnail($id, $size, $attr) . $after;

        if($return == TRUE)
            return $output;
        else
            echo $output;
    }
}

 
The downside is that it won’t recreate all of woo_image()’s features. However it shouldn’t cause issues with most themes.

Download: http://wordpress.org/extend/plugins/recent-posts-plus

1: Title

Default: Recent Posts

This field sets the title of the widget. It works the same as every other widget.

2: Number of posts

Default: 5

Changes how many posts are displayed in the widget. Enter ‘-1′ to display all posts.

3: Include post thumbnail

Default: no

Displays the post thumbnails of each post.

If this option is hidden you may not have a theme with post-thumbnails enabled. You can manually enable and add post-thumbnails to each post or you can download the Default Thumbnail Plus plugin automatically display a default image.

4: Include post excerpt

Default: no

Displays the post excerpt of each post.

5: Show expert options

Default: no

Show/hide the expert options panel. These options should be used with more care.

6: Limit post title

Default: (no limit)

Limits the numbers of characters or words to display of each posts title.
Example: For the post title “Look at this title” setting this option to 7 chars would result in “Look at…”

7: Limit post excerpt

Default: (no limit)

Limits the numbers of characters or words to display of each posts excerpt.

8: Limit ellipsis

Default: …

Sets the string to append to post titles or excerpts that have been shortened.

9: Post date format

Default: M j

Sets the PHP date format to use when displaying the post date.
See http://php.net/manual/en/function.date.php for overview of the options available.

Note: the date format can be overriden in the output template, which allows for multiple date formats in one entry, see section “12: Widget output template”.

10: Thumbnail size

Default: 50 x 50

Sets the size of the post thumbnail in pixels.

11: WP_Query options

This is an advanced option that modifies what posts are shown in the widget. This option specifies extra arguments to use in the WP_Query request and as such is very flexible even allowing this widget to show pages rather than posts, show oldest posts first, or filter posts by tag or category. The WP_Query options must be specified in valid JSON format (validate here http://jsonlint.com/).

These are the default args that are sent to WP_Query:

{
"post_type": "post",
"posts_per_page": <same as Number of posts setting>, 
"orderby": "date",
"order": "DESC"
}

List of options:

{
"post_type": "post", //post, page, revision, attachment, any
"post_status": "publish", //publish, pending, draft, auto-draft, future, private, inherit, trash, any.
"posts_per_page": "5", //overrides number of posts setting
"offset": "3", //number of posts to skip over 
"post__in": [2, 3, 4], //only show posts 2, 3 and 4
"post__not_in": [2, 3, 4], //exclude posts 2, 3 and 4
"ignore_sticky_posts": "1", //ignore sticky posts or not. Default value is 0, don't ignore (requires WordPress 3.1+).
"caller_get_posts": "1", //ignore sticky posts or not. Deprecated as of Version 3.1 in favor of 'ignore_sticky_posts'.
"author": "1", //author ID
"author_name": "john", //post author's name, use 'user_nicename' (NOT name)
"orderby": "date", //none, ID, author, title, date, modified, parent, rand, comment_count, meta_value, meta_value_num  
"order": "DESC", //ASC or DESC
"tag": "cooking,baking", //display posts that have "either" of these tags
"tag": "bread+baking+recipe", //display posts that have "all" of these tags
"tag_id": "13",
"cat": "1, 2, -3", //category ID 1, 2 but not 3
"category_name": "articles,news",
"year": "2011",
"meta_query" : [] //see below
}

For a full listing see http://codex.wordpress.org/Class_Reference/WP_Query

Ordering by custom fields

You can change the sort order to be based on a specified custom field using meta_value and meta_value_num as the orderby option.

Note: The difference between meta_value and meta_value_num is that the meta_value_num is sorted as a numeric value (i.e. meta_value would be ordered as a string e.g. 1, 3, 34, 4, 56, 6 whereas meta_value_num would be 1, 3, 4, 6, 34, 56).

The following example would order posts by custom field rating showing in order of highest rated to lowest rated.

{
     "meta_key": "rating",
     "order": "DESC",
     "orderby": "meta_value_num"
}

Utilizing the meta_query option

Note: This option requires WordPress 3.1+

Filter or show posts with a certain custom field value using the meta_query option.

The following example would display posts with a custom field called mood with a value of happy:

{
    "meta_query": [
        {
           "key": "mood", //Custom field key
           "value": "happy", //Custom field value
           "type": "CHAR", //Custom field type. Possible values are 'NUMERIC', 'BINARY', 'CHAR', 'DATE', 'DATETIME', 'DECIMAL', 'SIGNED', 'TIME', 'UNSIGNED'
           "compare": "=" //Operator to test. Possible values are '=', '!=', '>', '>=', '<', '<=', 'LIKE', 'NOT LIKE', 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN'
        }
    ]
}

The following example would display posts if they have a custom field rating of between 5 and 10 or if they have a custom field mood with a value of happy:

{
    "meta_query": {
        "relation": "OR", //Possible values are 'AND', 'OR'
        "0": {
            "key": "rating",
            "value": [5, 10],
            "type": "NUMERIC",
            "compare": "BETWEEN"
        },
        "1": {
            "key": "mood",
            "value": "happy",
            "type": "CHAR",
            "compare": "="
        }
    }
}

12: Widget output template

This is an advanced option that modifies the output of the widget. You can modify the output with template tags and add custom classes or tags for styling.

By default the widget outputs posts in this format:

<li>
{THUMBNAIL}
<a title="{TITLE_RAW}" href="{PERMALINK}">{TITLE}</a>
{EXCERPT}
</li>

You can modify the output by including the following template tags:

{ID} The post ID
{THUMBNAIL} The post thumbnail IMG tag if it exists, otherwise nothing
{TITLE_RAW} The post title
{TITLE} The post title, will be trimmed if it exceeds "Option 6: Limit post title chars"
{EXCERPT_RAW} The post excerpt
{EXCERPT} The post excerpt, will be trimmed if it exceeds "Option 7: Limit post excerpt chars"
{PERMALINK} The post permalink url
{DATE} The post date, the format is defined by the "Option 9: Post date format" setting
{DATE[php_date_format]} As of 1.0.4: Customized date format which overrides the default date format setting. E.g. {DATE[l jS F Y]} would display like "Monday 1st January 2011"
{AUTHOR} The post author name
{AUTHOR_LINK} The post author website url
{AUTHOR_AVATAR} As of 1.0.7: Displays the author's avatar if available
{COMMENT_COUNT} The total number of comments, Trackbacks, and Pingbacks for the post
{META[name]} As of 1.0.5: Displays the value of the specified custom field. E.g. {META[Currently Reading]} or {META[Rating]}. Note: Only returns the first result.
{ELLIPSIS}...{/ELLIPSIS} As of 1.0.9: Overrides option "8: limit ellipsis" for the excerpt. 
                         You can use other templates tags within the {ELLIPSIS} tags but not PHP and it will only be appended to the excerpt if it is truncated. 
                         Example: {ELLIPSIS}... <a href="{PERMALINK}">(more)</a>{/ELLIPSIS}

Using raw PHP in the Widget output template

As of 1.0.7 you can add raw PHP code to the widget output template.

Note: This will require the PHP code you enter to be run though eval which will likely have a small performance penalty. However if you don't enter any PHP code eval will not be run. Be careful not to give untrusted users permission to modify widget settings since it could be a potential security risk.

The following example displays the author's avatar at 32px size:

<li>
<?php echo get_avatar(get_the_author_meta('user_email'), 32); ?>
<a title="{TITLE_RAW}" href="{PERMALINK}">{TITLE}</a>
{EXCERPT}
</li>

You can access some of the existing template tag values with the $widget_ouput_template_params array e.g. $widget_ouput_template_params['{ID}'] contains the current posts ID.

Examples of Styling the Output

The look of the widget output depends a lot on what theme you are using. By default the output looks somewhat like the image below. Thankfully we can improve this with very little effort and a few additions to your themes stylesheet.

The first thing you need to do is go to Appearance -> Editor and select the Stylesheet option on the right (it should be selected by default but just make sure). After that paste one of the following styles at the bottom of the stylesheet depending on the look you want.

Note these are just basic examples you can do a lot more with more with CSS. These examples also depend a lot on the theme you are using, more complex themes may require additional styling. Hopefully these examples can point you in the right direction.

.widget_recent_entries li {
    clear: both;
    margin: 5px 0;
}
.widget_recent_entries .wp-post-image {
    vertical-align: text-top;
    margin: 0 5px 0 0;
}

.widget_recent_entries li {
    clear: both;
    margin: 15px 0;
}

.widget_recent_entries .wp-post-image {
    float: left;
    margin: 0 5px 0 0;
}

.widget_recent_entries li p {
    margin-top: 5px;
    color: #707070;
}

.widget_recent_entries li {
    clear:both;
    margin: 5px 0;
}

.widget_recent_entries .wp-post-image {
    vertical-align: middle;
    margin: 0 5px 0 0;
}

The above example has the thumbnail size set to 25px x 25px.

.widget_recent_entries li {
    clear:both;
    margin: 10px 0;
    text-align: center;
}

.widget_recent_entries .wp-post-image {
    margin: 0 5px 0 0;
}

.widget_recent_entries li a {
    display: block;
}

The above example has the thumbnail size set to 100px x 100px.