Go to
imageshack.us in your web browser. Select "image" next to where it says "Upload:", and then click the browse button. A window will come up allowing you to select the file from wherever you have it saved on your computer.
After selecting the photo off your computer, just click the "host it" button. The window will change after a few moments (depending on your internet connection, it may take up to a minute for the image to be uploaded), giving you a whole list of urls and stuff. Just copy the bottom one (next to "direct link to image") and paste it here so we can see it ourselves. To see which line to copy, just look at the arrow in this screenshot:
[your screen should look something similar to this]
If you want to save people the trouble of clicking the link, you can copy the line of text which has "Hotlink for forums (1)" written next to it (which is a little higher up the page than the one the arrow is pointing to in my pic). That one already has image tags on it, so you can just paste it directly in here and we'll be able to see the photo.
Is that what you needed help with?