The Internet standard requires that picture files be either jpeg or gif files, with the respective extension of .jpg or .gif. GeoCities servers require in addition that the files not be too large.
The picture file must be uploaded by one of two methods. Go to the file manager
( http://www.geocities.com/members/tools/file_manager.html ), enter using your membername and password, and arrow down until you reach either a set of five text boxes, each with "browse" to the right, or the message that you cannot use EZ Upload. If you cannot use it you should go to http://www.geocities.com/~answerpoint and learn how to get and use the program WS_FTP.
If you find the browse boxes in the file manager, click on a browse button. You will see the root directory of your hard drive. Use arrows to move through your directories to the name of the file you want to upload.Click on it. If an "Open" box appears, click on that too. Your file name will now be in the text box (and you must never type into these boxes). Click "Upload". Virtually immediately (or soon if the system is very busy) your file will be copied to your directory at geocities.
The page you want the picture on must contain an HTML reference to your picture file. A simple one is <img src="filename.ext"> with your file name and extension.