There is an inverse relationship between print size and resolution (if you increase the print size the resolution decreases and vice-versa).
To get good results when inserting an image into a research poster, the image should be printed at a resolution of at least 200 pixels per inch (ppi).
Images that look good online may not be high enough resolution to look good in print at the size you want them to be.
Watch the video below to see these concepts in action:
If you use images from the web, make sure you are not breaking copyright law. You can ask permission from the source or use images that are licensed as Creative Commons. In addition, government images usually fall in the public domain and are free from copyright.
For more information, consult our Copyright FAQ.