are .png max 1200 pixels wide?

[bvanevery]

My original was 1440x900.  I think it got downsized to 1200x750 when I attached it.  Want to make sure it wasn't something goofy on my end.  I'd rather not downfilter if I can avoid it, as informationally it's better for a pixel to be a pixel.  I suppose I could try cropping it to 1200x900 and see if it'll attach without modification.

[bvanevery]

I've now done a lot of experiments with various cropped image sizes.  I can't remember the answer to my original question, but I can probably figure it out if I look back over my posts.  Looks like the largest image size I've ever managed to attach, is 1200x900.  Looks like every 1440x900 image I submitted, was downscaled by the website to 1200x750.  So I will guess that any image with a dimension larger than 1200, is downscaled until the max dimension is 1200.

I also know that 800x800 is the maximum size that one can use, and still have the image be inlined.  It will display at 50% size, then if you click on it, it will instantly expand to full resolution.  Any larger than this size, and it will trigger a popup window instead, which is slower to load and display.  Also these popup windows display at reduced resolution, often 75% size.