Which version of Blocs are you using? I had a similar issue to this that appears to have been fixed in the latest Beta release of 2.3.0. I had some issues of swapped images displaying incorrectly in lightbox which may be connected perhaps? Try a test file in the Beta as I understand it isn’t backwards compatible with 2.2.
I’m having the same issue. I have a carousel and have removed some photos and replaced with other photos. When previewing in a browser (even if the browser hadn’t previously been used to preview this Blocs project), I’m still seeing some of the old images. I can see that the path indicated that it’s a cache preview file somewhere in Blocs data. Does anyone know how to clear the Blocs preview cache? Warm Regards, Randy