Hello.

I made a set of 23 walls. These were rejected because some of the patterns were apparently too big and because it needs tweaking. I'm not sure what tweaking it needs so please help.

All the walls are seamless, btw.

Yeah, the patterns do look quite a bit too big to me on many of those. The cream with the pink flowers looks about right in scale, but the rest seem too big. Compare to the normal size of patterns like that - for example, the red/blue paisleys are going to be almost 2 sim-feet long. In a real wallpaper pattern, those paisleys would be no more than a foot long, more like 6-8 inches. Same with the sort of blue pineapple/pinecone type pattern - that's a 3-foot wide pattern if it stretches over a whole tile, and should be sized down so it's at least two repeats per tile, more like a 1.5 feet per "pineapple."

Also, are you building your textures at 256x768 or 256x512? Your finished patterns need to be 256x512 but you should build your textures at 256x768 so they're the right proportion - otherwise, they'll look stretched in-game. Some in-game shots of these tiling over several tiles each would be nice too.

Yeah, after it was told to me, I realized they were too big.

When I first got the patterns I didn't want to resize them because they would get blurry. Every time I scale things down they tend to get that way. I'm not sure if it's the program I use (gimp) or if it has something to do with my graphic card.

Is there any way to work around this, to scale them down and still keep the quality?

GIMP shouldn't be too bad at scaling down. Scaling up is usually a problem, but scaling down should work okay. You could always do a very low sharpen filter afterward.

I don't know much about gimp, but I do know that there's three bicubic resample options in photoshop-bicubic, bicubic smoother, and bicubic sharper. That might not be immediately apparent because the default (in photoshop at least) is bicubic already.

I resize very large files down for web on a pretty regular basis, and in my experience you do get a fair amount of blurring if you downsize a lot. A trick you might try is resizing down in chunks--for example, downsize 50%, then 50% again, rather than 75% all at once. (Scuse if math is wrong.) Usually when I need to keep a lot of clarity in a significant downsize, I'll size down halfway, run a mild sharpen as HystericalParoxysm suggests, then finish downsizing. This keeps the sharpen from being too obvoius while preserving more of those details.

A long answer for a short question, but I hope it helps.