You need to convert the gifs to pngs in a graphics editing program such as GIMP/Paint.NET/PaintShopPro/Photoshop. They are located within the 'images' directory of the forum root. (There a heck of a lot of images though, so I hope you have a lot of patience)
In images/statusicon to be exact, forum_new.gif forum_old.gif are probably the ones your looking for.
Quote:
You would then have to a mass Search and Replace of '.gif' with '.png' in your templates and also edit the Main CSS background images from '.gif' to '.png'.
Good luck I guess...
AdminCP -> Stlyes and Templates -> Replacement Variable Manager and enter something like this in
Search for text: forum_new.gif
Replacement text: forum_new.png
this will update your style rather then attempting to change them all manually.