Silvera theme is using Magnific Popup for showing slideshow and images.Gutenberg editor
1.Gutenberg editor
If you are using Gutenberg editor and you want to allow your visitors had possibility to open image in popup window you must press your picture and in right side you will see properties of picture – choose ‘Media file’ here:

2.Classic editor
If you want to allow your visitors had possibility to open image in popup window you must choose ‘Media file’ when you add image(3). You can write caption(1) and alternative text(2):

You can see the caption under image on your website:

In popup window you will see text that was written in line ‘Alternative text’:
