Loosing transparency

I have some textures that I created some time ago and found I needed to modify one of them. After a search I found that I had lost the original from my HDD (smack wrist – no backup), so I saved a new copy from ‘in-game’. Editing this I found that the new copy had lost its transparency, not a big deal in this case, but can anyone tell me where I went wrong while saving from ‘in-game’?

What raster editor are you using? By the sound of it, I'd guess Photoshop 7.0. If that's the case, upgrade to 7.0.1 immediately, and read the Transparency Guide at the top of the forum to learn about alpha channels. PS 7.0 was highly flawed, and prevents you from making/viewing alpha channels properly.

In any case, when you download an image from SL, the transparency data is on the alpha channel, right where it's supposed to be. Most high quality raster editors, all versions of Photoshop included, will not display alpha transparency by default. The reason is that alpha channels don't automatically have to mean transparency; they could mean whatever you want them to mean, literally anything. So an intelligent raster editor knows enough not to make any guesses about what you might be using any particular alpha channel for. Imagine, for example, if you wanted to use the alpha channel as a bump map or a lighting map or something (SL can't do use alphas for these purposes (yet), but other 3D programs certainly can), but your paint program insisted on showing it only as a transparency map. That would really suck.

An alpha channel is just a numerical data map. Showing that data as transparency, or bump, or shine, or anything else, is the job of whatever destination program the image is being made for (in this case, SL), not the job of the raster editor.

If you want to see the alpha data as visual transparency, copy the alpha channel to a layer mask. Just remember to delete the mask before you close the file. TGA's are inherently layerless, so they cannot contain layer masks.

Thx Chosen. I'm actualy using Photoshop CS2, but I a raw beginner with it. It is probably that I was fooled into just thinking the alpha had gone, i'll go back to the manual