Graphics and Illustrations

Sometimes, the best way to support the message is to use charts, graphs, scientific graphics, illustrations, or digital renderings. Follow these standards when providing graphics and illustrations for


To make your graphics accessible to all users, follow these guidelines.

Alternative Text

Provide alternative text that represents the content and function of graphics. NREL web content specialists are available to write and answer questions about alt text.

Color Reliance

Do not use color as the only way to convey information. To ensure graphics do not lose meaning when colors are removed, view the image in black and white to see if it’s understandable. 

Consider using other methods—such as texture or symbols—to convey the content. NREL designers can help you modify graphics to convey information without relying on color.

A graph that uses color only to convey information
Example of a chart that uses color and shape to convey information

Example: Shapes were added to the lines to differentiate the lines without color.

Color Contrast

Elements that convey meaning, including components in charts and graphs, must have a contrast ratio of at least 3:1. Use the WebAim Contrast Checker to check colors. NREL designers are available to help with color selections.

An graphic with low-constrat text.
A graphic with high-contrast text

Example: The original image had low contrast between the background and text. Both were changed to increase contrast.

Text in Images

Important content should be coded as HTML text, which is directly accessible to screen readers.

A graphic with text embedded in the image.

Example: The text in this graphic is important content and should be coded.

Responsive Design

The 21st Century Integrated Digital Experience Act (IDEA) requires that all government websites and applications be mobile-friendly. 

Text and other components that convey information should be large enough to read on a small screen.

Charts with small text

Example: The text in this graphic is not legible on mobile. It was fixed by breaking the charts into three images that stack on mobile.

Charts with small text

Example: Consider context. In this example, the text is small on mobile, but the image was used to demonstrate a concept, not convey actual data. The client wanted to demonstrate the ability to display data in this format. The actual data wasn't important.

Use HTML text instead of embedding text in images to allow the text to rewrap for smaller screens without making it smaller.

a screenshot of a web pages using an image as text.

Example: The floated image of text on this page is hard to read at small sizes.

Interactive Graphics

Consider interactive graphics to help tell your story. Work with your designer and developer to ensure they are responsive and accessible to all.

Develop cost-effective technologies for deeper waters.
Deploy large amounts of reliable, clean power.
Create jobs in operations, construction, manufacturing and more.
Expand supply chains including tailoring port infrastructure to support development.
Help revitalize port and manufacturing communities.
Bring power onshore to areas of high demand.
Ensure environmental sustainability and ocean co-use.

Search Engine Optimization

Page load time is a primary ranking factor for search engines. Images should be optimized to allow web pages to load quickly on low-bandwidth connections. Typically, web images should be no larger than 100 KB, and the entire page should not contain more than 1.5 MB of graphics.

Avoid embedding text in images. Important content should be coded as HTML, which is searchable and helps pages rank higher in search results. See the example above.


Use colors from the NREL color palette, and check with an NREL designer to ensure your graphics align with NREL branding.


Include titles for charts to help users scan the page and understand, at a glance, what your chart is about. 

To improve usability, also consider the amount of information presented in a single graphic. Simplify charts, graphs, technical illustrations, and renderings so they are not difficult to read on small screens or too complex for the highest levels of the website.

Bar graph light
Line graph light

Example: These charts are legible on small screens and are not overly complex.

Page load time is essential for web usability. Keep file sizes small and limit the number of graphics on the page to help the page load quickly.


When considering images for feature spaces such as the homepage or research site homepages, only use high-quality photos that follow our photography criteria.