Texture resolution question

When generating a texture in PSP for example what resolution should you generate the image at?

I have been using 512x512 pixels and after uploading find that when the texture is applied to the surface it has to be stretched or shrunk to fit the face. This leads to a distortion of the intended texture.

What is the recommended resolution to eliminate this?

To fit a rectangular face undistorted, you should upload an image that has the same aspect ratio (ratio of width to height) as the face you are going to apply it to. The client will stretch it to suitable multiples of two for upload, but it will stretch back when you put it on the face and use the edit dialog to make it one repeat per face in both dimensions.

Well, sort of ..... After all, since SL brings in images with dimensions that are all powers of 2, you have limited flexibility with aspect ratios. If you create an image with some odd, non-integral aspect ratio, SL will squish it on upload. So, for example, if your image measures 620 x 327 pixels, it will arrive in SL as a 512 x 256 image. So what you have to do is think in simple aspect ratios to avoid drastic squishing, and then gently * do any necessary stretching in SL to make the texture fit the actual dimensions of your modelled surface. See Chosen Few's excellent sticky on dimensions, aspect ratios, and file formats at the top of the Texture Tips forum for ideas about how to do this with the least pain.

* EDIT: By "gently," I mean that you can't regain any resolution that was squished out of the image on upload, so you have to be aware that stretching a texture very much will cause some distortion. If you made a 620 x 327 pixel image originally, uploaded it, and stretched it back to 620 x 327 pixels, it would not look as sharp as when you made it.

I'm not a skilled texturer; I just use simple procedures to keep myself sane.

The last thing I do when working on a texture in Photoshop- when everything else is done but for the final save to TGA, I resize the image in Photoshop to the dimensions I want in Second Life. That way, I'm not surprised by the dimensions that Second Life chooses for the texture. Plus, I trust Photoshop to do the resizing more than I trust Second Life to do the resizing. (I don't actually know whether there is a difference in quality between resizing in Photoshop or by Second Life; I'm just superstitious.)

After uploading the image, one of the first things I do is note the aspect ratio that I intended for the texture in the Description field, which helps jog my memory as how to apply it to surfaces later.

Good tips, thanks.
I use PaintShop Pro X2 but I don't think it makes much difference except PSPX2 has an output of .png which means there is no further change of file format necessary.
PSPX2 has an annoying problem it doesn't create lines of even numbers of pixels rounding them up to the next odd number. I had begun to create a complex image when I discovered this ( I had been using PSPV7 which works) so had to recalculate the width of bars and lines so that when resized by SL they would camne out correctly. Your way could mean a whole new time saving for me. Thanks again.