Images...

What file format do images imported need to be? mpeg, gif, bmp?

They need to be Targa (.TGA) files.

They can be compressed or uncompressed, that doesn't matter.

They need to be 24bit colour depth.

If you want an image to have a transparent / see-through area, you need to create an alpha channel and save that into the .TGA file.

It is better for the system if your image dimensions are in multiple of 2. For example, 128 x 128, 256 x 256, 512 x 512, etc.

512 x 512 is pretty much as high as you should need to go for most things. That's a pretty good level of detail. Larger size images will just take a long time to load, and place a higher strain on the system.

Need Adobe Photoshop.....mmmmm...need to load that up.

bit depth apparently doesn't matter...

i've uploaded 16-bit TGAs with no problem. if you've got an image that only has a few colors, saving as 16-bit will save you some upload time, and will also allow the texture to show quicker for everyone else, being 33% smaller than the equivalent 24-bit image.

if you are using an alpha channel for transparency, i believe you NEED to save it as 32-bit TGA, otherwise the alpha channel will get dumped. if you are using photoshop 7.0, it will not save the alpha channel properly regardless of bit depth, and you will need to get the fixed TGA plugin here .

Yeah I've accidentally uploaded 16bit images before. They uploaded just fine, but they were pretty detailed, so naturally the 16bit ruined the colours in them and they looked like crap in-game. Bleargh.

As for 24bit vs 32bit for alpha channel stuff. I use PaintShop Pro saving at 24bit and it always retains the alpha channel, provided that you remember to hit "Save Mask To Alpha Channel" first.

The TGA reader should be able to read most Targa files. There are a few exceptions, but if you try to upload a file that isn't supported, a dialog box should appear saying so.

You should also be able to upload JPG files and BMP files. For the highest quality, though, BMP and TGA are both better choices than JPG, since JPEG uses lossy compression (ie, it thows away some information to save space). Also, for the highest quality, you'll want to upload files that are a power of two in each dimension (although not necessarily the same power of two). For example, 64 x 128, 512 x 32, and 1024 x 1024 are all ideal sizes. To run as quickly as possible, Second Life stores _all_ images with dimensions that are powers of two: any rescaling that's required adds a little blur.

You probably shouldn't bother converting 24 bit TGAs to 16 bit. The colors won't be as accurate and we recompress all images into our own format during the upload process anyway, so you don't really save 8 bits per pixel.

If you have an image file that won't upload and doesn't generate a dialog box, please email it to [email]support@secondlife.com[/email] so we can fix the bug. Likewise if you have a file that isn't supported and you really think it should be, feel free to post in the Feature Suggestions forum.

Hope this helps!

Aaron

Ehh are you talking about uploading textures??? I always use the JPEG format... Ofcourse jpeg can't have an alpha channel

A couple of additional notes...

As Aaron noted, uploading textures as 16-bit won't actually significantly affect the size of the texture or people's viewer performance - we convert the texture to a 24 or 32-bit progressive wavelet format, and we render all of our textures as 24 or 32 bit on the system.

Also, if you've got a non-transparent texture, you're better off uploading it into the system as 24-bit with no alpha channel, rather than 32 bit with alpha. It doesn't significantly impact file size (as it's really easy to encode the alpha channel), but it DOES have implications for the rendering engine. Fully opaque textures and objects are drawn in a way that's faster than potentially transparent objects, and you may also have noticed that you can get sort order issues on textures/objects that are transparent.

It's on the list of "things to do" to test texture that are being uploaded to see if they need the alpha channel or not, and also to convert those textures which are on the system which don't need alpha to non-alpha textures, but in the meantime, you'll probably be much happier with the results when you use 24-bit textures without alpha if possible.