bumperbyrnes
I do feel for you.
Listen the changes you require to blend correctly with your site, so that it looks visually pleasing within all areas would take a developer maybe 2/3 hours allowing for any hiccups along the way.
I would suggest you maybe ask for this. (Would like to offer my time but am really busy)
As to online image optimiser there are so many.
http://tools.dynamicdrive.com/imageoptimizer/
http://www.imageoptimizer.net/Pages/Home.aspx
This link gives bout 10 and some good reading.
http://www.webdesignbooth.com/12-really-useful-image-optimization-tools-for-web-designers/
I use Adobe Photoshop always, so also here's some good reading about what you should achieve an have.
http://www.webdesignbooth.com/12-really-useful-image-optimization-tools-for-web-designers/
Good Luck