Many PhotoBucket images can still be saved that show a watermark. When opened on PhotoBucket domain, it's removed, a clean image is hosted (payware incentive scheme). Saving other lost images on WayBack is a matter of odds/luck if image was captured. Keeping the forum private for a decade+ and a robots.txt ban ensured they couldn't be captured, so if the link wasn't shared elsewhere, it's long gone... Sadly, most ImageShack images are gone permanently, they were the worst, ~90% lost...

[9-5-2021] Giantbomb.com recently disabled their static.giantbomb.com subdomain for image hosting, now they're all served via www.giantbomb.com and slightly different prefixing. I clocked about 4-5 avatars using that, and 30 forum threads after searching. They can be saved with a little grunt work, but the clock is ticking. Some got saved by WayBack under the subdomain at least, but not all.