For a school survey, I am including images as a part of the question. E.g A question will have an image of some animals and children will have to identify them. Right now I am not able to zoom in the image. Nor am I coming across any options on how to resize the image. Most of the queries/support related to images are about how to resize images which we capture through the questionnaire and none about how to increase the size of display images. Please help.
If you mean, zooming in during taking picture on Collect, you can zoom in or out. If you are struggling with the image size on Aggregate server, you may need to customize the device camera settings.
I'm not aware of that ability existing in ODK Collect--the ability to zoom in to increase the size of an image. Disclaimer: I'm using an older version of ODK Collect myself; but I don't believe this feature exists in the latest version of Collect, either.
You could certainly set up your form in a certain way to create a bespoke implementation of this feature. By that, I mean that you could have set up your question screen as a single question group with the appearance "field-list". If you do that, then on the same screen you could have your question, your picture, and at the bottom you could add a "button" where, when selected, the user can go forward to see a larger image. By "button", I mean essentially a select_one at the bottom of the screen with the text "Zoom", for example. And then on the next screen you would have a "note" question with a larger version of the image on the previous screen.
If you are following me, I think you would agree that this isn't the best "UX" for your use case, especially for small children. But this is the only way that I know of to do what you are looking to do.