The preferred dimension of an uploaded/linked graphic is 640 pixels or less in width.

Using the Got Attachments Feature
Any graphic wider than 600 pixels uploaded via the "got attachments" feature will be auto-thumbnailed down to 200 pixels. Anything between 1 and 600 pixels wide is shown as is, unless the image file is very big, in which case it is thumbnailed and displayed using 1 to 3 column-spanning cells and as many rows as necessary for all attachments. Wide GIF files are displayed in thumbnail view as a JPG file, but when the thumbnail is clicked they display full size as a GIF file.

At this time, all .png graphics uploaded are reduced to 200 pixels.

The image below was uploaded as a 1600 pixel-wide .jpg file. The system auto-thumbnailed it to a smaller image that is clickable to see the original large version.



Using Image Tags for Linking Off-Site
Any graphic wider than 700 pixels linked off-site using [img] tags will not be resized, and it will blow out the right margin of the posting window. The extended margin will affect the entire posting page, and it can render the thread difficult for you and others to read. If this occurs, mods will edit the graphic to include a "width" statement, changing the graphic size. Please be considerate of others when posting images.

If you must use "inline" images from another site, you can also bury width, or width and height attributes in the image html, to stop margin blowout. If you see a wide external image, "hey-mod" it so a mod can edit in a width attribute.