Resize pics

Maybe u could tell me what I am doing wrong
I copy pics like from FB but when I try to use them like for wallpaper on my iPad it only takes the middle of the picture and crops all the outside. I cannot find where to shrink them. I tried to edit them but when I slide the size down. The second I remove my fingers it pops back to full size

 

Here are a couple of threads discussing the changes in how iOS 7 changed the way wallpapers are handled.

http://www.ipadforums.net/ios-7/114647-wallpaper-cropping.html
http://www.ipadforums.net/ipad-help/115213-setting-wallpaper-ios7.html

A lot of people are unhappy with the inability to use wallpapers the way they used to. Apple may or may not change this in future version of iOS. How much feedback they receive on the subject could make a difference; though Apple being Apple, you'll probably never know why they do or don't do something. You can send feedback to Apple here: Apple - iPad - Feedback

Remember, no matter how much you may feel like letting off some steam, ranting doesn't get listened to nearly as much as politely making your point.

In the end, for now at least, you simply have to find wallpapers that you like that look good with the new limitations.