Since this post was first published in 2018, several new resources have emerged, and some links have changed. We’ve updated this list to ensure all links are active and added two new, high-quality sources for free scientific imagery.

Pictures are essential in making scientific research more accessible and memorable.  Papers, posters, and presentations can all benefit from accurate, visually appealing diagrams.  While graphs and micrographs are important figures, they are not always sufficient to illustrate pathways and mechanisms, or to captivate audiences.  No one wants to spend hours drawing cells and molecules by hand or splurge on stock images they’re only going to use once, so I’ve compiled a list of my favourite places to find free scientific illustrations. I hope you find it useful!

1. Servier Medical Art (SMArt)

This is an excellent resource for anatomy, biology, and medical illustrations.  You can download specific items or entire sets of images. Everything is contained in PowerPoint presentations, so you can easily edit and combine your chosen elements. The material is covered by the Creative Commons 3.0 license, meaning you can share and edit the material as long as you give appropriate credit. Updated for 2025: Now offers 3,000+ free medical images under CC BY 4.0 license.

2. Somersault 1824

Disclaimer: this resource not free, but rather “pay-what-you-can.” You could technically download it for free, but I would strongly suggest chipping in what you can for these professional-looking, elegant illustrations.  The creators have PhDs in biomedical sciences as well as artistic expertise. Everything is available in a standard colour scheme, making it easy to mix and match.  The images are PNGs with transparent backgrounds so they can easily be dragged and dropped.  The work is covered under the Creative Commons 4.0 license meaning it can be shared and adapted for non-commercial purposes. Update for 2025: Still “pay-what-you-can,” offering custom science visuals and publication figures.

3. Public Health Image Library

Digitally colorized scanning electron microscopic (SEM) image depicts a number of yellow colored, Yersinia pestis bacteria, that had gathered on the proventricular spines of a Xenopsylla cheopis flea. The Y. pestis bacterium is the pathogen that causes bubonic plague. Source: National Institute of Allergy and Infectious Diseases (NIAID) via PHILThe Public Health Image Library (PHIL) is a database of images from the Centers for Disease Control and Prevention (CDC) in Atlanta, USA.  The database includes photos, illustrations, and videos, many of which are available in high resolution.  Images are often in the public domain and free to use, but it is requested that you credit and notify the content provider. Update for 2025: Offers photos, illustrations, and videos from CDC, many in the public domain.

4. Wikimedia commons

Yes, good old Wikipedia made the list! It contains millions of files that are categorized and searchable. Images can be in the public domain or covered by creative commons licenses; find out which license applies in the Licensing section of the image page.

5. Pixabay

Pixabay is a good source of free science stock images (with the option to pay for higher-resolution photos). There are some high quality diagrams of cells and DNA as well as pictures of scientists at work.  They are free to download and use.

6. Pexels

Pexels is another source of stock images, including some interesting science stock photos.  They are free to use for any reason and do not require attribution.  Use your judgment with stock images: they may be eye-catching but inaccurate. Speaking of which, the original featured image for this blog contained some left-handed DNA (thank you to some observant scientists on Twitter for alerting me).  Here’s an easy way to tell the difference  so you don’t end up in the Left-Handed DNA Hall of Fame.

No, that’s not how GMOs are made.

7. Adobe Stock

Adobe Stock is full of high-quality images.  Large companies often use these images in their marketing campaigns, and for good reason! There are numerous 3D illustrations that are detailed, artistic, and scientifically sound. For this reason, a basic Adobe Stock membership is $30 USD per month.  However, you can sign up for a month-long trial and download up to 10 images for free. You have to enter your credit card information, but if you cancel within the first month you won’t be charged.  A “pending” charge appeared on the credit card account, but it disappeared within several days.

3D illustration of cancer cells from Adobe Stock

New for 2025!

8. NIH BioArt Source – 🆕

Launched in 2024 by NIAID, this free biomedical art library offers high-quality illustrations created by professional medical illustrators.

9. NASA Image and Video Library – 🆕

A searchable archive of space, science, and Earth imagery, all free to use with attribution.

These are just a few of our favourite image sources at StressMarq Biosciences, please comment any others you’ve found helpful!