By following the basic principles outlined here, we can make our LibGuides more accessible to individuals with disabilities.
(WebAIM: 2014)
This screenshot (figure 1) is 350px wide and looks good on computer screens and on an iPhone 5.
I used MS Snippet tool to capture the image, edited it in MS Publisher 2010, saved it as a .png file, and then I resized and autocorrected it with MS Picture Manager.
Figure 1. PubMed screenshot 350px wide.