Karrde

Displays thumbnails from Flickr based on the user/group/tag you provide.

Flickr Thumbnails Widget

Displays thumbnails from Flickr based on the user/group/tag you provide.

pekastel

Lets you pick a Creative Commons picture from Flickr and use it anywhere you want on your WordPress installation. The plugin will maintain attribution to the original Flickr author to keep peace with the CC Attribution License.
This plugin makes use of the newest WordPress 3.4 feature that allows to embed html in image captions, and also is backward compatible with older version of wordpress as well.
Features:
<ol>
<li>Search photos from flickr with creative commons license by tag (since version 1.2 you can search by any type of license)</li>
<li>Preview image results.</li>
<li>Define the order of the search results.</li>
<li>Automatically add image caption that links back to the original flickr owner.</li>
<li>Lets you use the standard features provided by WordPress for image editing:
<ul>
<li>Image alignment.</li>
<li>Cropping.</li>
<li>Rotating.</li>
<li>Flipping.</li>
<li>Resizing.</li>
</ul>
</li>
</ol>

Flickr – Pick a Picture

Lets you pick a Creative Commons picture from Flickr and use it anywhere you want on your WordPress installation.

Flickr Thumbnails Widget vs Flickr – Pick a Picture