Image implementation

[jehendeoff]

This implementation adds support for still image and GIF (while removing the old GIF provider and renderer).

In order to do so I used the image crate which supports all those formats, however I only tried and tested : GIF, png, bmp, webp (image), jpeg, ico

if you see anything that needs to change or bug(s), don't hesitate to tell me.

[jehendeoff]

I'll try to update the "unknown gif" gif that appears when there is an issue

[not-jan]

Nice code! Thank you for your contribution :)