I’m customizing the Prestashop template and I was stuck with some images that they were not available for being changed.
Then I found that some of the images are represented using data URI scheme.
Inline images use the data URI scheme to embed images directly within web pages. As defined by RFC 2397, data URIs are designed to embed small data items as “immediate” data, as if they were referenced externally. Using inline images saves HTTP requests over externally referenced objects.
Then, I found this webpage webSemantics which offers the way to generate the data URI.
I also learned how they are cached, so you have to clean the cache from your hosting to show the changes.