Renegade Greyscales... looking for tips/help

[jigsaw]

the other day i went throught the STEX and dug up what i think to be the best GS (greyscales) maps on their. i collected about 60 maps.

i am going through and rendering all of them, to see how they turn out in-game.

some of them work fine, but some of them wont render at all. i have opened the bad ones up in photoshop elements, checked their setting against known working GS, and they appeared fine, however still dont work to render a map.

any help and advice is sought.