Raise or Lower Function?

[twinpeaksenterprises, LLC]

When im porting a picture into the designer program it takes you through a few steps. At first it lets you crop the picture, it also has the raise or lower. Can someone tell me what exzactly what that does for the pattern. The "help" dont exzactly tell you and its hard to see what is actually happening to the pattern when doing so. Can someone tell me how it is beneficial to either raise or lower. Can this also help improve the quality of photos imported from paint.

[swhitney]

the raise and lower function can eliminate the "background" of the scan, leaving only the actual item.

[TIMCOSBY]

much to photos seems thers not much height diff to deal with.