Albin

With this pluginyou can face two goals:
· File Replace Sometimes you have an image used in several spots (slider, gallery, feature image, …) and if you remove it and upload it again, as it gets a new ID, you will need to select the new one all around but you could forget a place. To avoid it, use this plugin.
· File Rename Sometimes we upload a file as it comes from the mobile camera and later we realize that the file doesn´t have a ver SEO-Friendly name. Here you can rename the file.
None of both functionalities will breake any link where the image is pointed by its ID but this action doesn´t do a Search and Replace along the post entries.

FileRenameReplace

This plugin let the user renaming or replacing files without breaking links.

fumidzuki

The upload image filename change to random unique filename. (target extension. bmp, gif, jpg, jpeg, png).

Unique Rename Image File Upload

Everything worked very good, I wanted to enable support for .mp4 and .wma and it was easy enough to navigate into the file and copy / paste some text.

It would be cool if you added some notes to let people customize the length of uniqid during the random creation part. Right now it just spits out a 32 CHARACTER word.

FileRenameReplace vs Unique Rename Image File Upload