Hello azdolfan,

you have to transform your pictures in some kind of graphics program (I used simple paintbrush) to save them as png. Open it, click save as and then in the drop down menu under the field where you enter the name of the file pick png format.

PNG is a format that is used for web sites and therefore should be smaller than the gif or jpg format.

As to your second question.
What I do when I need to mass find and replace is that I copy the code into notepad and do (CTRL + H) find and replace. Notepad retains no formats so there is no problem with spoiling html code.

If you have problems to do it, I can do it for you but you need to send me your html as well as original and desired picture location on your server.

mike