Alt text is one of the most important aspects of image optimization. While you may think that simply using keywords relevant to the picture in the title is sufficient, you should also optimize alt text to supplement it.
Image alt text, or alt tags, are ways to give Google and other search engines more context for a photo. Although Google is better at identifying what's in an image, alt text tells it exactly what it is so people can find it.
Google is also more likely to rank images with relevant titles and alt text higher than images that don't have these features.
Many businesses tend to misunderstand the purpose of alt text. For instance, you may have an image on your blog of a 3D-rendered pile of money on a white background. The blog itself is about "Best Ways to Save Money," but the image itself shouldn't include alt text referencing the blog itself. Google only cares about what's in the image itself. Some businesses might include "ways to save money" in the alt text to help rank for the blog's search terms, but the appropriate alt text should instead describe the content of the image.
Optimized images with appropriate titles and alt text can subsequently help improve the ranking of whatever page they're on, indicating to Google that the page has original and optimized content that's worth ranking. People searching for a specific image that's relevant to your business may also stumble upon your website in an image search, helping you extend your outreach.