Watermarks/copyright

If you feel comfortable with photoshop 5 then definitely use it as it is powerful and you will know your way around it. Alternatively there is an online graphics backage which I often use called splashup (splashup.com). It is totally free and is seriously powerful, it contains all the features from photoshop you tend to use but discards the specialist functionality which the average user never touches when editing photos making it very simple to use.

You better upgrade your photoshop to the CS (Creative Suite). Or at least to photoshop 7 is good enough. With CS, you can find many awesome features inside including what are you asking for here, a watermarker. Since CS series are developed in this internet era, Adobe has includes all the internet user needs for digital imaging purposes. But before upgrading, please check the system requirements whether it suitable with your computer. Good luck and have a nice day. Happy mylotting.

hmmm.. as far as i know, photoshop would be your best option. specially if you're already used to photoshop. you mentioned photoshop 5.. i'd also suggest you get an upgrade. get Photoshop CS series

Even Microsoft Paint could do a simple edit to defend your images- simply create a new text box, and write "Copyright *Your Name Here*". Its both one of the great strengths and weaknesses of the internet- anyone can just copy an image onto their desktop.