It looks like the guide and some instruction has been provided above, but here is a more detailed breakdown if you still feel stuck
Some image hosting URLs are found here:
https://imgur.com/ and
https://tinypic.comIf using imgur, you'll want to make a new post, using the button found in this picture
Select the "browse" option to find the photo you would like to upload.
Once finished, hover your cursor over the photo until the option "get share links" appears on the top right found in the picture below.
Once opened, you should get a window with four choices. Select the BBCode forums option, and copy it.
After you have this link copied, feel free to directly paste it into your topic If you've decided to use tinypic (which is a bit faster/easier in my opinion), simply select the "choose file" option from the homepage and locate your photo. You have the freedom to resize the picture here if you feel it is too large or small.
After you've chosen your picture, click the big green "Upload" button. Once it uploads, it will provide you with all of the sharing links to the left of the picture.
Please feel free to message me if you have any questions or can't seem how to move forward!