I have been reworking a web site to optimize for SEO. One thing I did is to optimize Images using Googles Webp Format. But Webp is not supported on any version of Safari.
My question is: What can I do to load one image (Webp) if supported or load another like JPG if not supported.
It could be great if it is something like the Audio or Video TAG
<audio controls>
<source src="horse.ogg" type="audio/ogg">
<source src="horse.mp3" type="audio/mpeg">
Your browser does not support the audio tag.
</audio>
Add your code like as below and it should most probably work.
<picture>
<source srcset="image.webp" type="image/webp">
<source srcset="image.jpg" type="image/jpeg">
<img src="image.jpg">
</picture>
More details are mentioned here in this link.
I assume you are using only 1 image in src (in img tag) if that fails to load then you are trying to loan any other image. So, You can use
<img src="invalid_link" onerror="this.onerror=null;this.src='other_image_url';">
Hope this helps.