I'd like to thank Chuck in Killbuck from whom I blatantly stole the following tutorial for my own selfish purposes. It has been modified slightly for the Critter Cafe forum.

How to post pictures in forum threads.
To post pictures into a forum you must upload it to a website that allows linking to it. Either by getting a free hosting site or a paying account with one. Free sites are great but they only allow you to upload a certain number of pictures and only allow you a certain amount of bandwidth per day.
Below I've put some links to some of the free sites I have found ranked among the top. You can check them out to see which one, or more, suits your needs. Each one has a different limit as to the amount of pics, bandwidth, size, etc in its free section. I have used Photobucket for a couple of years and have hundreds of pics and animated graphics stored with no issues or running out of space. (I think P'bucket allows 10 mg of free storage)
You'll want to look closely at the FAQ's where they have it to get an idea as to how the site operates. I also advise you to have a graphics editor program, or use MSPaint, in order to resize your picture if need be. (Photobucket has an easy user friendly photo editor) Each site has a limit as to the bytes you can download per picture. This must be done before you can Upload. Several will do this automatically for you.
http://www.imageshack.us/
http://photobucket.com/
http://www.snapfish.com/
http://www.villagephotos.com/
http://www.walagata.com/
http://www.imagecave.com/
http://www.thefilebin.com/
http://www.myonlineimages.com/
http://www.imgzone.info/
http://www.imagelink.org/
http://www.watotron.com/watupload/
Once you have choosen your website to use, the rest is
pretty easy to do to post your pic to a Zaar thread.
If you are on a website and like a picture or a graphics just Right click on it and click on Save Picture As and download it to a special place or folder on your pc where you can find it. Most of the sites above work the same way. You log in and go to your photos or album and then:
1. Locate the link to Upload A Picture and click on it.
2. Click on Browse and locate the picture on your pc.
3. Double click on it and then click Upload.
4. Each site will vary a bit but you want to find the picture you uploaded and find it's URL. Some may have more than one type.
If so look for the one that says to use with forums, boards, ebay, etc.
If they show [ ], { }, or whatever, choose the one with the [ ] brackets. Like this example from the Photobucket site.
Some will have a link to Copy URL with the picture, if so click on that.
That copies it to your clipboard to use on Zaar. Others you may have to Highlight and Copy the URL under the picture, once again saving it to your clipboard.
5. Once you have the URL copied go the Zaar thread you want to insert the picture at.
6. Click on Reply or Quote, whichever is appropriate, and at the top of the message box Click on Image. This will put [img] in the message box.
7. Now Click just after [img] and paste in your URL. Be sure there is no space.
8. Now Click the Image button again. This will put [/img] after your URL. Again make sure you have no spaces from start to finish. A space will break the link and it won't work.
9. You can now type anything you wish on a new line down.
10. Click on Post to send it, or Click on Preview to see how your picture will look on the thread. After a Preview, Click on Post.
11. You are now done and can go back to the thread.
TIP: When you are in Zaar and wish to post a picture you have on a website, it's easier to do if you have TWO windows open. While you are in Zaar hit Control+N, or click on File/New/Window and open one. Use that window to go to the website with your picture. This way you are able to work between the two sites by clicking in the task bar at the bottom to switch back and forth. It's far more easier to keep track of what you are doing and a lot faster.

How to link to a picture on the web:
Many times I just want a photo for a single one time only use. No need to go through all of the bother of downloading it to Photobucket or your image hosting site. Follow these very simple steps. THIS ONLY WORKS IF YOU USE THE MOZILLA/FIREFOX BROWSER. Disregard if you use a version of the Microsoft IE browser.
For example, say you need the image of a poodle. Do a Google search for
poodle images. I'll use the first image as an example.
1. Click on the image to open it to its full size.
2. Now
right click on the image and select copy image location.
3. Paste the image location between the ][ brackets with no spaces. [img]paste image location here[/img]
4. Photo will display and you have used no space in your Photobucket account. It takes like 30 seconds. Easy peasy.
Feel free to use this thread to practice your skills we won't make fun. Really. Honest.

Nana nana boo boo!