Image Resolution?

I have an image which when I view it in my version of Paint Shop Pro seems alright but when I upload it and apply it the edges of the lines become fuzzy.
I set the size to 512x512 before uploading and don't know whether that is right.
The image consists of a star pattern of lines crossing at 60 degrees to each other so it is inevitable that some aliasing is going on but is there anything I can do to make the lines sharper when displayed inworld?

increase you anti-aliasing settings for SL? ... it also may help to have thicker lines, and make sure the image has finished rezzing. another factor is screen size, vs actual size... if it's rendered far from it's normal size you'll notice visueal problems more (aliasing at large % of screen size and fuzzyness at small %)

I 'm not sure I understand you.
Do you mean my viewer's antialiasing ? If so how would that affect other resident's viewers.
I have thickened the lines as much as I can and still make a reasonable image.
The image has fully rezzed and of course at a distance the lines look solid but if you take the camera close in they appear fuzzy.
I think it has something to do with the lines I drew in the drawing application they had to be based on a 24 bit colour and thus became shaded off the line due in part to the angles being 60degrees to each other and not at right angles. I am definitely not an expert a these drawing things and need help.
Would it help if I attached the image here?
If I could it keeps failing to attach anything.

I have researched this question of antialiasing and found that despite having a recent graphics card I do not have the ability to employ it.
Now if I don't have it how many others do and would it be better to tune the image to match the majority of aother residents capabilities?

In addition to what has been said about anti-aliasing, you might also experience some compression artifacts, depending on colors and overall complexity of your picture. Sadly there is no way to avoid those except for small textures, which can be uploaded in lossless mode. You can check the impact artifacts have on your texture if you save the uploaded texture from SL back to your harddrive, import it as a new layer on top of your original image and set the layer mode to difference.
Also, I don't know about the scale of your texture in-world, but keep in mind that a single image will always look pixelated on very large faces ( I think that's what Void meant with screen size v. actual size)

The image in question is the playing surface on the top of a 2.5m cylinder. You can see an example in-world at Peaceful Retreat 192, 52, 32 or 158, 102,30.
I have also dound that the graphics card I have has the ability to do antialiasing and am investigating its capabilities. The inability I referred to is because I tried to use the preferences way of adjusting the anitialiasing which doesn't work; how fast technology changes.