508 Compliance Checking
Section 508 exists to, among other things, ensure access for people with vision impairments who rely on various assistive products to access computer-based information, such as screen readers, which translate what's on a computer screen into automated audible output, and refreshable Braille displays. Certain conventions, such as verbal tags or identification of graphics and format devices, like frames, are necessary so that these devices can "read" them for the user in a sensible way. The standards do not prohibit the use of web site graphics or animation. Instead, the standards aim to ensure that such information is also available in an accessible format.
A good tool to start your exploration of accessibility issues is the WAVE Web Accessibility Evaluation Tool.
Source: Section508.gov - https://www.section508.gov/content/laws/summary-section508-standards