I keep putting all of 'em like that in envelopes and am waiting for a very, very long winter night.
Here are some considerations:
1. Color (is it pink or dark pink)?
2. Perf or Imperf
3. Then if Perf, what is it?
4. Coil?
5. Watermark and if so, which one?
6. Grill? And if so, which one?
6. Rotary/Flat or Offset printing
7. Different types of papers (to add insult to injury!)
It's unlikely that mere pictures will narrow those down - or perhaps narrow them down to 2, 3 or more possibilities.
However, I find narrowing them down to say 2 possibilities is almost more bothersome than not knowing at all!
Perhaps the two trickiest variables are the shades of color (after all the stamp is 100 years old - did it fade or not?) and then the different types of printing (rotary/flat/offset). The difference in printing type is often only a millimeter or so and once again these stamps are 100 years old and shrink and expand.
Don't mean to be a "negative nelly", but you're probably just going to have to roll up your sleeves and do all the various measurements, watermark tests, etc.
Here's a link that gives some idea of what's involved:
http://www.jamesdire.net/W-F.htmlBTW, there is a lot of stuff on the Internet to help you out.