The Blockheads Wiki:Image guidelines

Proposal for image guidelines:

File formats

Although The Blockheads Wiki supports png, gif, and jpg, PNG should be used whenever possible. JPEGs are lossy, and lost image quality that can't be recovered. See this image for a comparison.)

As quality has already been lost, do not just save JPEGs as PNGs.

File names and dimensions

In general, use descriptive names for images. Do not upload images with names like "File:Picture.png" or "FIle:IMG 056.png". Also, remember to categorize all uploaded images.

Example	File name	Dimensions	Notes
	File:(item name) Icon.png	40x40 pixels	All item icons, not including blocks or HD icons
	File:(block name) Icon.png	80x80 pixels	All block icons, must be taken on a retina device
	File:(item name) Big.png	160x160 pixels	All items with no overworld render, should be identical to inventory icon at 4x Background should be File:Gradient.png
File:Dirt.png	File:(block name).png	160x160 pixels or larger	All block icons
	File:(block name) HD Big.png	160x160 pixels or larger	All block icons, must be taken on a retina device
	File:(item name} Big.png	160x160 pixels or larger	All items with overworld render
	File:(achievement name) Ach.png	120x120 pixels	All achievement icons, must be taken on a retina device on iOS 7