Low res texture in UV map with repetitive polygons I have a really simple object with less than 20 polygons, that is used on a platform for my game. I was able to model and unwrapped it, but I want to resize all the side polygons so they are 32px high, and stack them together (as they are all the same).

Also, I wanted to know if it was possible to set the resolution of the UV-map viewport (where the 2D texture is displayed) so it has a resolution according to my target texture, and the polygons faces are aligned.

Here is the picture of what I have done so far:
In the UV Editor (as shown in your picture), select one of the 'sides' (position the mouse cursor over one and hit L) then hit ctrl P - this will make it fill the image vertically at 64px high. Now scale it by half S (.5). Do the same with all the other 'sides' (not the top or bottom), they should now sit neatly one on top of the other, and be 32px high. 
Position the 2D Cursor on one of the vertices at the bottom of the 'sides' (select a vertex and hit shift S > Cursor to Selected),



and then set the pivot to 2D Cursor.



Now grab G the 'bottom' and position one of it's vertices on the 2D Cursor and then scale (S) until the next vertex lines up as shown.



Do the same with the 'top'. Now all resolutions should be the same and the sides will be 32px high. I hope this solves the problem.