[SDL] SDL_Image alpha support

[Mattias Engdegård]

>Then it's maybe just me who doesn't know how to do it in the gimp, i
>played around with it but it still doesn't seem to work. When i save the
>image in the gimp i use the layers dialog box to make the pixels
>translucent and i save it to a file ( tried png, tga and tiff ), but when
>i open it again it has lost the translucency, i tried with rle on tga,
>with the keep transparency checked - but still no luck.

please post a link to sample files so I can have a look at them, preferably
one of each format