Music-dad

Try this, open your photo, then go "save as" give it a new name, and save it as a jpeg, the options for quality and size should come up as part of the save process, every art program I have does this, you may need to look for a tab "properties" during the save.

Lowering the dpi is good too, during the save as, you will most likely be asked what res. you want, or you can do that it the art program before saving.