Note: this issue does not appear to occur on Sierra.
If you find that you are crashing when uploading images, or doing anything that opens a file picker, then read on.
When you open a Finder window from SL, if you are in either Icon mode or Coverflow, and switch to either List or Columns mode the viewer will still crash. You need to do the following to work around this:
You should now be able to upload - and perform operations with the file picker in general - without crashing. You can even switch between List and Columns. But, you can never switch to the Icon or Coverflow.