Current rules
[Storyboarding]
Storyboard images must be at a reasonable size for their usage. For most uses (e.g. full-screen images), the maximum is 800x600 pixels, although 640x480 is highly preferred. The editor is 640x480 at default, so there's really no need to use anything larger for full-screen purposes.
The maximum dimensions for tall or wide scrolling images are 640x1440 and 1920x480 respectively. This is for the sake of gameplay performance, image loading time, and filesize.
Storyboard images must be at a reasonable size for their usage. For most uses (e.g. full-screen images), the maximum is 800x600 pixels, although 640x480 is highly preferred. The editor is 640x480 at default, so there's really no need to use anything larger for full-screen purposes.
The maximum dimensions for tall or wide scrolling images are 640x1440 and 1920x480 respectively. This is for the sake of gameplay performance, image loading time, and filesize.
I am unsure of how much images actually impact performance. I think we can tell by strangeprogram that SB Load has little to do with it, and using a 2000x2000 image will only ever add 1.0 to the SB Load, making it somewhat useless as a determinant.
A lot of people use 1024x768 images as their backgrounds. In order to decrease the filesize of the beatmap, they might use that background in the storyboard. Well guess what? They can't according to these rules, since the "max" is 800x600. But then "scrolling images" are allowed 1920x480. For that reason, we shouldn't base it on some dimensions, but rather a number of pixels. Like, for example, 1920x480, which is 921600 pixels. That would mean the maximum image sizes are:
1920x480
640x1440
960x960
1108x831
Certainly you may think some of these numbers are a bit strange, but that's because they don't exactly fit into the method, but they all share the same maximum pixel value. What if you want to make a circular scrolling image, not a linear scrolling image? Or a diagonal one? You would be limited to the 800x600 value. What if you want a better quality scrolling image? 1536x600 is against the rules too, even though it has the same number of pixels.
There might also be a maximum dimensions (1920 length and 1440 height for example) to prevent a 912600x1 image, but in that case setting a maximum of 2000 for any dimension will work. It will stop any real abuse without removing any creativity.
So here's my revised rules
[Storyboarding]The first rule could actually be moved, as it is a guideline, not a rule, and the second rule can cover it easily.
Storyboard images must be at a reasonable size for their usage. For most uses (e.g. full-screen images), the maximum is 1024x768 pixels, although 640x480 is highly preferred. The editor is 640x480 at default, so there's really no need to use anything larger for full-screen purposes.
The maximum size of a scrolling image is 921600 pixels (1920x480, 640x1440, 960x960, etc...). This is for the sake of gameplay performance, image loading time, and filesize.
Avoid going over a 5.0x storyboard load to help prevent lag on older computers. Resizing some of your storyboard images may help with this.As I said earlier, the actual size of the images in the storyboard has nothing to do with SB load. Should just link to this: Tips on reducing SB Load (to eliminate lag!)