Here are some answers I lately got from the G2F author.
@EMKAY:
you can use special function when reading BMPs -> it's possible to choose colors which are to be converted to Atari colors.
What do you mean by "G2F's promotion" ?

It's just free will - everybody can use G2F as it is available at AtariArea and here.

There are still many beta versions and official versions come rarely.
You are maybe wondering only few people use G2F ? Well, laziness is everywhere ....
@PPS:
DLI works best in most cases, the rest should work as well but not so often.

The widest screen mode (48 bytes) really takes very much time and ANTIC may not come in time with it... But there are some pictiures that work OK with that width and there are others that won't work.
That's why there are so many ASM settings to help you adjusting it.
When "saving to GED" feature is added, there will be more chances to come in time.
Save XEX: creates .BAT procedure that copies files into main catalog and compile them all and after that it copies the result to new long filename.
When there's X-ASM updated with long-filenames support, everything should be simplier and without so many hassle. FOX (XASM author) promised to do such fix.
At my computer SAVE XEX works everytime I wish, by the way.