nkyre

WordPress upload file names can be quite predictable sometimes, especially if uploading from the same camera – DKIM1004 comes after DKIM1003. If not all of the content on your site is public, this can be a problem as people can snoop on your media folder by guessing file names.
This plugin prepends a short 8 character hash to the beginning of every uploaded file. For example, DKIM1004.jpg turns into 8df8078e-DKIM1004.jpg. The hash is not cryptographically secure and just makes it a bit more difficult to guess file names.
The plugin works on all upload file types and all sizes of a given image get the same prefix.

Media File Name Guess Preventer

Prepend a random string to media file uploads to prevent file name guessing.

Sean Butze

Many users do not compress or resize their images before uploading them into a post, and oftentimes WordPress’s maximum upload limit of 2MB-10MB is still too large to prevent the insertion of photos that can signficantly slow down a website.
WP Image Size Limit allows an administrator to set a custom file size limit that is specific to image files and smaller than WordPress’s general file size limit.
This is especially useful when you need to put tighter restriction on image uploads but want to preserve the ability to upload larger files of other formats (audio, video, etc.).

WP Image Size Limit

Just what I needed to tamp down those designers who think it's okay to use 20MB images!

Brilliant

Adds a new setting under Settings -> Media where an admin can set a maximum upload file size for image files.

Media File Name Guess Preventer vs WP Image Size Limit