The "GIF" descriptor in AROS Build and IcarOS includes the entire GIF family, both GIF87a and GIF89a (partically mixed acronym Images and Animations)
On AROS One x86/68k i split, I used "GIF87" (Descriptot GIF) for Images and "GIF89" (Descriptot GIFAnim) for Animated Gifs.
Of course, "GIF89a" is an extension of "GIF87a"
"GIF87" Normally is used for Images.
"GIF89" Normally is used for Animations
Multiview through the Descriptor uses the datatypes designated in the Descriptor, so even if the fils have the same extension, Multiview will be able to Show the image or animation.