These are tiny, and I'm already wearing glasses. *rubs eyes* I will try.
*magnifies this to 200%*
1. Men at Arms (???) Yes -- the mirror (feminine symbol) is when Angua joins the watch.
2. Pyramids
3. The Light Fantastic
4. Unseen Academicals
5. Moving Pictures (love the 1,000 Elephants!) =D
6. The Amazing Maurice and His Educated Rodents
7. ???? This is too hard. =(
8. Soul Music
9. Making Money
10. Guards! Guards!
11. *magnify, magnify, magnify... to 500%* Oh, this is Thud! =D The pawns and the cow. (Where's the cow?)
12. Aha - Wyrd Sisters!
13. Equal Rites
14. Mort (?)
15. Is it Eric? (lots of devils and a wizard -- could be anything that involves the Dungeon Dimensions)
16. Reaper Man
17. Wizards, broom and map? No idea.
18. Small Gods
19. Lords and Ladies
20. Invisible men, battle, shield and sword??? No idea.
21. Hogfather
22. Jingo
23. The Last Continent
24. Carpe Jugulum
25. The Fifth Elephant
27. The Truth
28. Thief of Time
29. No idea. Three grannies, disabled man, battle, sword and shield???
30. Hrr ... what the heck -- is it Feet of Clay?
31. The Colour of Magic
32. ??? Money and time? Time is Money?

33. Time is OK???
34. Theatre, music, death, wizard. What?
35. Ah, Feet of Clay!
36. Fewer blue people in a blue circle. What is this, the Smurfs?

37. Going Postal (envelope + crazy)
38. Aha! Wintersmith!

39. The Wee Free Men (land under wave)

40. All I can see is a crown. The Shepherd's Crown???
41. Sourcery!
This is fun, but way too small. I couldn't see some things. =(