I'm mostly interested in infantry and cavalry officer uniforms, around 1880 if that's not too specific. I'll appreciate any links, and thank you in advance.
Your best bet might be to look up conflicts of the period. As a Brit with a fairly keep interest in our relatively modern military history the two 'big' wars I'd suggest you look at that are around the period you're thinking are:
I only suggest these wars as they're potentially the most famous of the period but a 1/2 decent website with lots of contemporary pictures is here. They've a collection of battles on the left ordered chronologically and you might find what you want there.