i need the picture of 1366*768 ,but almost are not ,can i change the resolution of them ,if i can ,how to do?

You really can't. I use that res, but none of my wallpaper's are the size. Win7 it rather good at scaling images into wallpaper.

Download GIMP, install it, open image in GIMP, then in the menu:

- click image -> scale image
- enter desired resolution and click scale
- click file -> export and save as png

Is not even needed... all you should normally do is set the image as wallpaper, but use the correct scaling method. You should always keep the aspect ratio, and depending on the image's dimensions, generally you will want it in an overflow layout (that is, stretched until the image fully covers the background, even if some edges of the image are left outside the monitor's area).

I have thousands of wallpapers, and I don't try to scale them to the right size... I just set the scaling algorithm at "use wallpaper" time.

Kumacuda said:
You really can't. I use that res, but none of my wallpaper's are the size. Win7 it rather good at scaling images into wallpaper.

i did as what you said ,but the pictures would wether be blurry or deformation.Though the i don't like the way,thank you all the same.

And thank you to the other two. i will try the ways you advised.