For Slideshows:

Just click on the slideshow link and a new window will open. Then use the normal controls to move through the images.

If you’re using an Apple or Android device automatic (Flash based) slideshows shown as slideshow or Slideshow 1 will not play unless you use a special browser. This is simple Click here for how to do it.

For still photos:

This could be part of a Gallery where several photos are shown as a set of touching tiles or circles.

1. To view a larger version of a single image in a separate page – Right Click on the image then Left Click on “Open link in new tab” or “Open link in new window” (Note this sometime may not work, but see 3. below).
Or…
2. To display an enlarged gallery – Left Click on an image. Then use the large side arrows (or swipe an image sideways) to move between images.

3. To get a full screen view of the current image, scroll down and click on “View full size…”

4.  To close the enlarged gallery, left Click outside an image or press ESC

If not part of a Gallery eg a single image surrounded by text, first click on the image and a new window will open displaying just a larger image of the photo.

Then either:

try pressing F11. This will open up a full screen view of the photo (with most browsers). To return to normal view press F11 again.

Or

try clicking on the enlarged image again which could give a further enlargement (with most browsers).

When you’ve done, click on top right X to close the separate window.