Images can make digital content easier to understand, but they can also create accessibility barriers when they are poorly designed or implemented. Missing alt text, insufficient contrast, color-dependent information, and inaccessible text embedded in graphics can prevent people with disabilities from accessing the same information as other users.
An image accessibility checker helps identify and address these barriers before visual content reaches users. From checking WCAG color contrast and simulating color vision deficiencies to improving color palettes and remediating image alt text, free accessibility tools can make image testing a practical part of everyday content and design workflows.
This guide explores some important tools for checking and improving image accessibility.
Why do images need accessibility testing?
An inaccessible image can exclude users in several different ways.
Users with vision impairments
Screen reader users may rely on alt text to understand images. If an informative image has no appropriate text alternative, its purpose or information may be lost.
Users with color vision deficiencies
If an image/visual depends exclusively on red and green to communicate distinctions, some users cannot easily perceive it.
Users with cognitive or learning disabilities
Clear visual hierarchy, readable typography, predictable color use, and meaningful descriptions can make visual information easier to understand.
This is why image accessibility testing should be considered during image creation – not after the graphic / image has already been published.
Key Accessibility Checks for Images
Before exploring individual tools, it helps to understand what an accessible image review should cover.
Check alternative text
Meaningful images need an appropriate text alternative. The description should communicate the purpose or essential information of the image, rather than simply describing every visible detail.
The right description depends on why the image is being used.
Decorative images, on the other hand, generally should not receive unnecessarily verbose descriptions.
Check text within images
Text embedded in banners, infographics, advertisements, charts, and social graphics can create accessibility problems.
Important information should be presented as actual webpage text rather than being available only inside an image. This improves scalability, translation, searchability, and assistive technology access.
Check color contrast
Contrast is especially important when an image contains text, icons, labels, charts, or other meaningful graphical elements.
WCAG Level AA requires a minimum contrast ratio of 4.5:1 for normal text and 3:1 for large text. Check whether meaningful graphical elements and user interface components within an image have sufficient contrast against adjacent colors. Under WCAG 1.4.11 (Non-text Contrast), important visual information such as icons, graphical controls, chart elements, form controls, and other essential graphical objects generally needs a minimum contrast ratio of 3:1.
Important: WCAG 1.4.11 is different from WCAG 1.4.3 (Contrast Minimum), which primarily addresses text and images of text. When checking images, teams should evaluate both where applicable: 1.4.3 for text and 1.4.11 for meaningful non-text visual elements.
Check whether color is the only visual cue
Do not communicate meaning exclusively through color.
Instead of:
Red = rejected, Green = approved
Consider:
Right symbol for ‘Approved’.
Wrong symbol for ‘Rejected’.
Color can reinforce the distinction but should not be the only way users identify it.
Essential Tools to Improve Image Accessibility
Instead of relying on one checker for every image, a combination of specialized tools can provide much better coverage.
WCAG Color Contrast Checker
The WCAG Color Contrast Checker is useful when designing image-based graphics containing text, icons, buttons, labels, or other visual elements.
Users can select foreground and background colors or enter their color values to receive an immediate contrast result. The checker provides WCAG AA and AAA information and distinguishes between small text, large text, and UI components.
Useful for:
- Social media graphics
- Website banners
- Infographics
- Promotional images
- Text overlays
- Charts and graphs
- UI mock-ups
- Presentation graphics
Color Blindness Simulator
A color blindness simulator helps designers understand how an image may appear to people with different forms of color vision deficiency.
This tool allows users to upload or paste an image and simulate conditions including:
- Deuteranomaly
- Deuteranopia
- Protanomaly
- Protanopia
- Tritanopia
- Achromatopsia
- Other black-and-white simulations
It supports common image formats such as JPG, PNG, GIF, and JPEG.
Best use cases:
Use it for infographics, charts, data visualizations, maps, social media images, marketing creatives, product dashboards, and diagrams.
Accessibility Color Palette Generator
Accessibility is easier to achieve when accessible colors are selected at the beginning of the design process rather than corrected later.
Accessibility Color Palette Generator helps identify color combinations that meet WCAG contrast requirements. It can be used to develop palettes for text, backgrounds, and graphical elements.
It can help designers:
- Create accessible brand palettes.
- Select text and background combinations.
- Identify WCAG AA / AAA-compatible combinations.
- Build accessible UI colors.
- Design more readable graphics.
- Reduce repeated contrast corrections.
This is particularly valuable for teams developing design systems, because an accessible color palette can be reused across websites, applications, presentations, marketing materials, and image templates.
Free Accessibility Checker
Although it is a broader website accessibility tool rather than an image-only checker, complements image-specific testing.
It can help identify accessibility problems on a webpage, including issues associated with images and their implementation.
This is useful because an accessible image file can still be implemented incorrectly on a webpage. For example:
- An informative image may lack alt text.
- An image link may have an inadequate accessible name.
- Decorative images may be unnecessarily announced.
- An image containing essential information may have no equivalent text.
*Do not forget to include manual review for better user experience.
From Accessible Images to Inclusive Experiences
An accessible image is more than a graphic that passes a color test. It must communicate its intended information to users with different ways of perceiving and interacting with digital content.
The most effective approach combines specialized tools: use a contrast checker to validate color relationships, a color blindness simulator to identify color-dependent barriers, an accessible palette generator to make better design choices, and webpage-level checkers to verify how images are implemented. Human review then provides the contextual judgment that automated tools cannot.
Contributing to the Accessibility Community
As part of its commitment to advancing digital accessibility, we contribute free accessibility tools and resources to the W3C accessibility community. These resources are designed to help organizations, developers, and content creators better understand and address common accessibility barriers.
Reach out hello@skynettechnologies.com and our team will help to create clearer and more useful visual content for a broader audience.
