Rule

All diagrams must be drawn @2x the display article size (which may be significantly larger than the thumbnail size)

Rationale

Makes it easier for users to view the image at full size, and ties the image to its intended use.

Rule

Units of px are always used

Rationale

All images are eventually rendered to pixels, working natively in this unit prevents pixel-splitting and other degradations in quality during rasterization.

Rule

Page edge length must be a multiple of 80 px

Rationale

Makes it easier for users to add the images to Wikipedia articles.

Rule

All rigid objects (including text) must be bound to a coordinate which is an integer multiple of 8

Rationale

• Works well with Retina devices, as it allows easy scaling by factors of 2 and 1.5
• Helps preserve floating point precision since coordinates can be scaled loss-lessly by eighths
• Produces eight natural levels of “zoom”—12.5%, 25%, 37.5%, 50%, 62.5%, 75%, 87.5%, 100%. All of them can be scaled up and down by a factor of two (except the 12.5% level when going down). Four of these levels can be scaled up by a factor of 1.5 (25%, 50%, 75%, and 100%).

Rule

Thin annotation lines should be 0.5 px wide, white or black.