inserting jpgs and gifs

Hello all:

I've got a few pics in jpg and gif format that I'd like to add to a 
historical translation I'm now editing.  It's been a while since I've done

anything in html.  My question is:

Where do I put the pics before filling in the hypertlink?  In what 
receptacle?  They can't just hang there in the ether so to speak. The 
solution must be good for at least these os's: windows, linux, unix, mac.

What tags do I use to insert the pics?

Looking forward to relevant replies

ergo_sum