I have been uploading photo files to my agents at the guidelines recommended in the September 9th, 2009 article you posted titled "What You Need To Know About Uploading To MLS" . Yesterday I had an agent tell me the 800x600 pixels are too small. Up until now no one really complained about it. He also said the minimum should be 1600x1200 but prefers 2048x1536. What is the NEW standard everyone is using today? Is there a new standard?
The problem with recommending a specific size is that MLSs run a wide variety of system software. Because of this there is no such thing as a standard. Some MLS software does a good job at downsizing if you give them a bigger size than they like but in the past MLS downsizing has been notorious for mangling photos files so the theory has always been that if you give them the exact size they want they end up not touching the files during uploading. Here are my updated recommendations for figuring out what size photos to upload to your MLS:
Some readers have told me that when they call their MLS they have trouble getting photo specification information. Be aware that MLSs are set up to support their members (agents that pay them monthly fees) so explain that you are a photographer that supplies photos for their members and you are inquiring so you can better serve their members.