There is no probably no issue in the Foundry that has caused more discussion and debate than that of map size limits. Those of us who wield the Foundry stamps have recently been revisiting the size limits, and our unanimous opinion is this:
Since some small maps are being produced with a width of 630 pixels, and since the site's current user interface supports a maximum small map width of 630 pixels, then there is no reason not to set 630 pixels as the maximum small map width for everybody. Likewise, large maps may be created with a maximum width of 840 pixels, though as large map size is less of an issue we will continue to recommend 800 pixels as the ideal large map size.
The maximum size for the height of both small and large maps will remain at their current levels, 600 and 800 pixels respectively. This is based on UI needs, and is not currently open for debate.
We envision a future in which maps can exceed these size limitations, but that day is not yet here. When and if the site undergoes an interface overhaul, new standards can and will be established, but until then further changes in the size limits will not be discussed further.
So, to recap, these are the size limits we will be enforcing:
Small map: height=600 pixels, width=630 pixels
Large map: height=800 pixels, width=840 pixels (800 pixels recommended)
Andy, Coleman, Gimil, and Oaktown