What a weird thread !
It looks like Arfon was opening it regarding uploading pictures, so I go on on this topic.
Arfon, I don't think it should be any different from PC to Mac.
To publish pictures on the forum, there are 2 possibilities
1 - upload pictures directly from your computer's library
2 - upload pictures from a website where you previously stored your pictures.
1 - First, most of the pictures we take now with our digital cameras or smart phones are too big for the forum (jpg pictures on the forum can be 97.7 kb maximum). So your pictures will need to be reduced if you want to upload them directly from your computer.
There are many ways to reduce the size of a picture, though, I don't know the utility software on Mac.
Be aware also that the pictures you'll upload this way will appear on the forum only to connected members. By opposition to the second method where all the pictures are always visible to any visitor, which is much nicer I think.
So if you are not comfortable with reducing the size of your pictures and so on, the best option for you is the second option.
2 - Open an account on
Photobucket or
flickr.
I know a lot of members use photobucket, but I don't really like it : it is full of advertisement, it plays commercial video while you're working, and all these craps slow down the process. I find it really annoying to use. I gave up on it and now I use flickr, which is, to my opinion, much nicer to use.
To publish pictures from your flickr or photobucket gallery on the forum, you need to copy what is called the "BB Code" of the picture on your post.
How to get it ? On flickr, once you have uploaded the picture(s) on your flickr gallery, select the picture you want to upload on the forum (click on it to "edit" or "open" it), and click on the small icon you'll see at the bottom right of the window, looking like a frame (computer screen ?) with an arrow going out from it. This is the "sharing" icon. A box will open with 2 choices: HTML, and BBCode. Click on BBcode. Then click on the complicated-looking code in the window, it will be automatically selected (blue). Copy this code, and paste it on your post on the forum. Your picture will appear (in the preview or when you submit your post).
In the same windows, you can also chose the size of the picture (how big it will appear on the forum. I think that 500x375 is OK. If you want people to be able to see details, 640x480 might be a better size. After, 800x600 is really big I think.
If you use photobucket or another pictures storage website, the process is slightly the same, you need to copy the BBCode and paste it on your post, that is what is important.
Hope this will help
Good luck !