Edna Mae,
fishfriend is right - use a full reply. You need to host the pictures somewhere on the web. You can use your website or photobucket or flickr or something like that.
Once you have them hosted, just right click anywhere on the picture and choose Properties, which will give you the web address of the picture. Copy the web address of the picture.
Then, go to the forum post you want to post it to, hit reply (you won't see the options on quick reply, so choose full reply instead), then click the third icon at the top of the message space - you'll see a globe, an envelope & the next one is for pictures). Click it and you'll get a prompt to enter that web address (and here you just paste what you copied before).
Yes, please post some photos of him because that does sound like it is possibly worrying. Normal color change is one thing - but white spots are usually a pretty standard sign of disease. Is he also trying to rub or scratch his body on anything in the tank? He might do this if his spots are itchy.