In my portfolio I have case studies, where I explain a bit of my projects and place images of different sizes along with the text. While in some smaller images the user is able to click and view the large version, some other images are clear enough on the page (with no clicking the user is able to see the image in almost it's original size). So my options are:
- differentiate clickable images and non-clickable images (I didn't want to do that as it won't look so good when for example in one column you have an image with a border and on another an image without it)
- make everything clickable even if some images when zoomed in will just repeat the image
- keep the way it is, some images will be clickable and others won't.
The question is: Is it a real issue for users? If there is an image that is clear enough will they still try to click to see a larger version of it? Will they be more frustrated to try to click and nothing happens, or will they be more frustrated to click and see a similar image? (guess is more of an issue for touch-device users as they won't have any hover effect)