Size of background image?

Hello, I´ve been trying to find pictures for the background of my forum but they´re either too big or too small so that the image appears several times in the bacground. What is the right size of the image so that it would fit just...on its own. I want everything in the image to fit in the background and I don´t want it to be so small that you can see a side of another image.

you cannot determine the background image solely on that what you see.

members can have different resolutions on their screens, so if you can see the image perfectly and only once , that doesn't mean others will also see it.

the best way to add a background image is via CSS!. that way you can add an image and make sure it doesn't get repeated over and over.

if you are not to good with CSS, you can always find an image that is a pattern adn is seamless, that means it repeats without seeing the lines where the 2 images meet.

Thanks. I did have a look at the CSS thing but that´s a bit too complicated. A pattern it is so.

The best option for having an accurate background on all users' resolutions of their screens is to just make a simple 100x100 image (any size, as long as the width and height are the same size) that contains a repeated design. This is an example of what I mean:
(60x60)
If you set it as your forum background, it will repeat, but it won't show any lines that make it look like it's repeating.

whats the image you want to use?

good example rok

Oh I got the members to send in different ones, but it´s okay. I´ll go with the pattern. Although I just read a thread about fixing the width of the forum so maybe I can use a picture.
I´m so bad at all this stuff. I don´t understand anything about the codes and stuff.