well, now that you mention reiner, i found what that the image you provided differs greatly from the original reiner
set of ogre sprites
which are perfectly fine, clean grapics. did you build the sprite sheet yourself from the orginals (or was that image someone elses work)? regardless, that's a whole other ball of wax and easily remedied by building it correctly.
assuming you'll ask (and for anyone else watching this thread), you'll notice the same walking frames are originally sized at 96x96. the sprite sheet you provided had frames @ 64x64 and maybe this is where the image got messed up (using an ill-advised method of resizing). so, my question would have to be "do you need 64x64 frames or are the original 96x96 frames fine?".
if you need to resize the frames to 64x64, each direction of the walking animation is made up of 8 frames, so create a new 512x512 (8x64) image and do the following for each frame (assuming photoshop):
1) under Image, choose Mode > Indexed
via Image > Resize (bi-cubic checked. you could play with sharpen, etc but i don't think it's necessary) to 64x64
3) select all
4) copy & paste
(Ctrl-C & Ctrl-V) into appropriate location within the new 512x512 spritesheet image (i'd set the grid there to 64 px spacing to assist in placement via View > Snap To Grid).
for the remaining frames
6) apply magenta, rgb(255,0,255), via Paint Bucket
to brown background with same settings above (Tolerance = 0, etc). trusting reiner's sprites, you could turn Contiguous off
before filling to turn all brown background to magenta in 1 fell swoop via paint bucket
7) save & smile
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