This is a great website for Photoshop Element users. Some of the info is paid subcription but there are some free gems as well. They even have Elements Radio which of course is free.
This is one of their 'tips' from thier site
Don't Open That Huge Layered File! Instead...Sometimes you just need a quick look at a file, but if your layered file is 200MB, 300MB, etc., in total size, it's not going to be a quick look. That is, unless you know this little trick that lets you open a flattened version of that very same file, which will be dramatically smaller in file size (which means it will open much faster). Just press-and-hold Shift-Alt (Mac: Shift-Option) before you click the Open button in the Open dialog (using File>Open) and it will bring up a dialog asking you if you want to open just "the composite data." Click OK and a flattened version will open instead (leaving your layered version untouched).
check them out http://www.photoshopelementsuser.com/