This document provides information about the Acquia Web Governance accessibility check:
Is the image a flickering GIF?
What
This check does a review of large animated GIFs to determine if they flicker or flash rapidly. Images that flash more than three times per second or are visually intense can be hazardous to certain users and must be modified or removed to ensure safety and comfort.
Why
Flickering images are a significant accessibility concern because they can trigger seizures in individuals with photosensitive epilepsy. Additionally, rapid flashing can cause headaches, nausea, or dizziness for some users, and can be highly distracting or uncomfortable for those with cognitive disabilities or attention disorders.
Who
Affected users
This check affects the following users who have:
Photosensitive epilepsy: Who are at risk of seizures due to rapidly flashing images.
Cognitive disabilities or attention disorders: Who experience flashing lights as highly distracting or uncomfortable.
Other users: Who suffer from headaches, nausea, or dizziness when exposed.
Examples
Pass examples
A compliant image is one that either does not flash at all or flashes at a rate slower than three times per second. For example, a simple loading GIF with a slow, gentle pulse is acceptable.
A non-compliant image is one that flashes rapidly or contains high-contrast transitions that occur more than three times per second. This creates a high risk for adverse physical reactions.
This section provides information on how to review and fix the issue.
How to review it
Identify large animated GIFs on the page. You can use the Web Governance Browser Extension to identify these elements on the page or in the HTML source code.
Observe the animation to see if it flashes or flickers.
Determine the frequency of the flash. If it appears to flash more than three times per second, it fails the check.
How to fix it
Fix the issue with one or more of the following alternatives:
Replace the flickering GIF with a static image that conveys the same information.
Edit the GIF to reduce the flash rate to well below three times per second and ensure that the transitions are not visually intense.
Provide a way for users to pause or stop the animation immediately when they load the page.
Additional resources
This section contains useful resources for this subject.
This document provides information about the Acquia Web Governance accessibility check:
Is the image a flickering GIF?
What
This check does a review of large animated GIFs to determine if they flicker or flash rapidly. Images that flash more than three times per second or are visually intense can be hazardous to certain users and must be modified or removed to ensure safety and comfort.
Why
Flickering images are a significant accessibility concern because they can trigger seizures in individuals with photosensitive epilepsy. Additionally, rapid flashing can cause headaches, nausea, or dizziness for some users, and can be highly distracting or uncomfortable for those with cognitive disabilities or attention disorders.
Who
Affected users
This check affects the following users who have:
Photosensitive epilepsy: Who are at risk of seizures due to rapidly flashing images.
Cognitive disabilities or attention disorders: Who experience flashing lights as highly distracting or uncomfortable.
Other users: Who suffer from headaches, nausea, or dizziness when exposed.
Examples
Pass examples
A compliant image is one that either does not flash at all or flashes at a rate slower than three times per second. For example, a simple loading GIF with a slow, gentle pulse is acceptable.
A non-compliant image is one that flashes rapidly or contains high-contrast transitions that occur more than three times per second. This creates a high risk for adverse physical reactions.
This section provides information on how to review and fix the issue.
How to review it
Identify large animated GIFs on the page. You can use the Web Governance Browser Extension to identify these elements on the page or in the HTML source code.
Observe the animation to see if it flashes or flickers.
Determine the frequency of the flash. If it appears to flash more than three times per second, it fails the check.
How to fix it
Fix the issue with one or more of the following alternatives:
Replace the flickering GIF with a static image that conveys the same information.
Edit the GIF to reduce the flash rate to well below three times per second and ensure that the transitions are not visually intense.
Provide a way for users to pause or stop the animation immediately when they load the page.
Additional resources
This section contains useful resources for this subject.
Web Governance