Graphics: Image Sizes for SL
This is a guide on how to get the best from images you upload to sl for use within the client. When I say “Within the client” I am talking about pictures that are used by Second Life at specific pixel dimensions, for example Profile Pics, or Classifieds Picture.
Upload Sizes:
Second Life only allows you to upload images in certain aspect ratios, or rather it lets you upload in any aspect ratios but will resize to the nearest number.
These numbers are : 8, 16, 32, 64, 128, 256, 512, 1024.
Soo your image will end up being a combination of these numbers. You should always try to resize outside of SL as the compression SL will put your images through is fairly destructive.
For example, This is two textures that should appear the same pattern. One was originally 64*64 and the other was 64*96. During the upload process the 64*96 got resized to 64*64. Take a guess at which is which.
Image Sizes: (Advanced>UI>Debug Views)
All these images assume you have UI set to 1.0, This can be found under the General Tab of the preferences window (ctl+p).
I have got most of the common image sizes for you here, providing pixel dimensions and aspect ratio.
Profile Pic;
- 180*151 – 1.192:1
Profile Pick;
- 290*180 – 1.611:1
Profile Classifieds;
- 207*155 – 1.335:1
Profile 1st Life Pic;
- 135*151 – 1:1.119
Group insignia;
- 128*144 – 1.125:1
Search Classifieds;
- 400*300 – 1.333:1
Search Show Case;
- 500*300 – 1.667:1
Search Land Sale;
- 360*270 – 1.333:1
Search Places;
- 400*300 – 1.333:1
About Land;
- 180*135 – 1.333:1
There are a few extra images I need to find out the image sizes for but at the moment those web pages are not accessible from outside Second Life.
[edit 3/9/09: Appears there is a wiki page with this info now.]
How to make use of this info:
Now, from this info you have all you need to get the best of your images through Second Life Compression.
For example, Possibly the most important image here for most people, your profile Pic. At 180*151 both dimensions will round down to 128 rather than round up to 256. So best off start with an image of 256*215. This is the same aspect ratio as the profile pic but will force Second Life to round up rather than down. Any more that that size is a waste as people won’t see the image any bigger (dependant on web search coming back online). Once you have your image as you want it, I would recommend doing a further resize outside of Second Life so that your image size is 256*256. In this case the Second Life Profile will add pounds 
At this point I would also like to make a suggestion for the About land image. Going on what I have just said you’d be aiming for an image of 256*256. However, This same image is going to be also found in Search Places which is 400*300. So in the case of the About Land image you are going to want to go for 512*512 as more people are going to see the image in Search Places rather than going to your land and going to About Land.
As I have mentioned a few times. Second Life Search is accessible from the web usually. Parts of the inworld search are run on this system and are not part of the XML Skin. There are various images I would have also included but access to this part of the search from outside Second Life seems to have been restricted at the moment. I would have liked to be able to check through the html of those pages to get the details of these other images but I couldn’t.
[edit 3/9/09: Torley wrote up a similar tutorial here.]