Photo Gallery

To add pictures as blocks in the page, you can go to the insert menu on the right and click 'Images' to upload directly from your computer/device. That looks like this:

You can drag the image left/right to adjust its placement on the page.

Alternatively, you can go to 'Content Blocks' on the same menu tab and select one to arrange photos in a grid pattern, maybe like this:

Doing it this way will usually fix your aspect ratio to fit whatever template you're using, but you can double-click on an image to re-crop/zoom. 

Another way to display images is with a carousel, accessible in the same menu tab (but further down). That might look like this:

You can move the carousel around the page the same as for a normal image. While I don't believe you can interact with the carousel (e.g. navigating between images) on the edit page, you can click the Preview button on the top of this page (looks like a phone in front of a computer screen) to see what it'll look like for website users. You can add captions to images (which I've done for the first one) by double-clicking on the carousel, hovering over an image, clicking the text box button (should be the one on the right), and clicking 'Add caption'. You can also add alt text very similarly for users with a screen reader (e.g. visually impaired users).

The thing about a carousel is that it locks all your images in to the same aspect ratio, so if you have some landscape pictures and some portrait images, it might be hard to put them in the same one. You could do multiple carousels to get around this, though.