Thumbnails Manager helps you to manage your thumbnails within the administrator panel. You can define a default ratio for thumbnail creation, rename, change the description or even delete your thumbnails.
This is the very first time I release one of my own plugin. Maybe because it is a little bit more finished than the previous ones even if I can?t say I spent a lot of time on this one.
Well? In other words, be indulgent and please give me helping comments and any wish for the next version.
A small list of features:
<ul>
<li>Change the default ratio for the thumbnails.</li>
<li>Display images by pages.</li>
<li>Rebuild thumbnails.</li>
<li>Rename and change the description.</li>
<li>Resize of thumbnails.</li>
<li>Delete of images.</li>
<li>Thumbnails creation size strategy: scaling, maximum size, fixed size</li>
</ul>
New in v0.7:
<ul>
<li>Thumbnails creation size strategy: scaling, maximum size, fixed size</li>
<li>A bug correction (impossible to save ratio value)</li>
</ul>

Thumbnails Manager

Thumbnails Manager helps you to manage your thumbnails within the administrator panel. You can define a default ratio for thumbnail creation, rename,  …

Nolan Chou

Sometimes we forgot change our file to a available name. So the plugin can help you auto change your upload file. 
I will add a filetype option of setting in next version. 
And a rename popup before the file upload if you change setting in future, default value is post_name.

wp_upload_rename

Change upload filename to random characters / random numbers / date / other by yourself.

Thumbnails Manager vs wp_upload_rename