Description
If a graphic is needed to understand the content or functionality of the webpage, then it should be perceivable for people with low vision or other impairments. Enough contrast should be provided for graphics that convey important information so people with moderately low vision can perceive them.
What to Consider
Images Resizing
Resize images at the server, if they have an intrinsic size.
Large Graphics
Do not use images that cannot be rendered by the device. Avoid large or high-resolution images except where critical information would otherwise be lost.
Images Specify Size
Specify the size of images in markup, if they have an intrinsic size.
Non-Text Alternatives
Provide a text equivalent for every non-text element.
Color Contrast
Ensure that foreground and background color combinations provide sufficient contrast.
Background Image Readability
When using background images make sure that content remains readable on the device.
Measures
Do not use pixel measures and do not use absolute units in markup language attribute values and style sheet property values.
Resources
Mobile Accessibility: How WCAG 2.0 and Other W3C/WAI Guidelines Apply to Mobile
Mobile Accessibility Standards and Guidelines at W3C