I've been drawing all of my maps in Other World Mapper, exporting them, then uploading them piece by piece to roll20 for my campaign that I'm running. Unfortunately, I tend to draw large maps and roll20 only accepts files that are 10 MBs or less. Mine tend to be between 25-40 MB if they are main maps. As consequence, I go into Microsoft paint and split my maps up along grid lines such that each individual portion is less than 10 MB.
When I export on a grid, things start getting wonky. My specified pixel thickness for the grid lines is 4 pixels. While this does work on the vertical slices, the horizontal ones don't (they are 3 pixels thick, not 4). To make matters worse, the grid doesn't line up exactly with the grid that is defined in my owm file...its off in both x and y by about 1-3 pixels in both directions, making for very odd looking maps, especially since my corridors often have tiled floors.
My second bug I'd like to report is in regards to grid snapping. If you have Snap enabled (Edge or Center), I've noticed that the features and closed rooms do snap...so long as the angle is 0 degrees. If they are rotated any bit, the snap no longer works. With rooms, you can clear the angle such that it resets to 0, but you can't do that with a feature. No matter what, it retains that angle it is given.
I've been able to work around these bugs for 0.9.7, but it was working just fine for 0.9.6, so hopefully it shouldn't be that bad to fix.