You can upload pictures directly from your computer or phone to include in your post by using the "Attach" box. The "Attach" box shows when posting a new topic or a reply, but not when using "Quick Reply".
Images must be 200 KB or smaller. There's a maximum of 4 attachments per post and the total of all of them can't be more than 500 KB. Make sure you crop the picture(s) to show only what needs to be shown.
Many (free) programs out there that resize picture files - almost any photo program does it. If you resize the pictures right, they don't have to be big files to be clear. Just downsize them to 700 or 800 pixels wide. If you keep the jpg quality factor lower (50 or 60 is fine), it takes up a lot less space than at 80-90 with little change in picture quality.
I use
http://www.irfanview.com/ - works well and is free.
Many use
http://www.obviousidea.com/windows-software/light-image-resizer/ - also free.
You can also to a picture hosting site like
Flickr or
Google. Both are free and pretty easy to use.
You can then copy the direct IMG code from the hosting site and paste it directly into your post. Again, you want to keep the size down to 700-800 pixels wide so it fits on the screen without scrolling and so it doesn't take forever to load for people with slower connection.
Lastly, you might change the file name as you save it so you still have the high resolution version (I just add an e to the end of the file name so I know it's been edited).