Trimming the Fat
If you use the Move tool to reposition a layer, and a portion of the layer starts to extend beyond the edge of your document, Photoshop will remember the information beyond the edge (Figure 3.27). Therefore, if you move the layer away from the edge, Photoshop is able to bring back the information that was not visible. You can save a lot of memory by getting Photoshop to clip off all the information beyond the edge of the document (Figure 3.28). Here's a little trick for trimming off that fat. Just choose Select > All and then choose Image > Crop—no more wasted memory.
Figure 3.27. The original image. (multiple images ©2005 PhotoSpin, www.photospin.com)
Figure 3.28. After the image is cropped.
It also wastes memory when you ...