Trouble adding new pics with the OOB editor

[BogdanM]

I'm having trouble importing new pictures in the game. I've done it before (1 year ago) without any problems but now it doesn't seem to work anymore.

I've downloaded the trial version of Corel PSP X4, resized the pics to 180x60 (2:1 ratio), greyscaled, sharpened and tried both palletes "JASC_WINSP_ICON_PALETTE.pal" and "JASC_WINSP_PICPAL.pal". I than save the picture as .jpg and than manually change it's format to .lbm. Any idea what am I doing wrong?

edit: Btw the message I get when i try to use a new picture is "Invalid file". Also the game is patched to v5.5