The websites listed below offer great free tools for editing your images before placing them on your website.
Crop, resize, add text, add frames and more with these websites
Offers excellent options, more advanced - http://pixlr.com/
Find a Web Color
An excellent, free way to get a web color in the hex format (e.g. #4F5C67) - https://www.colorpicker.com/
Find Matching Colors
An amazing tool by Adobe - Color.Adobe.com
Add a Watermark