Is there a setting to enable "Find in page" / Ctrl f on pages that only have images?

In the Firefox browser, when I am on a page with only an image, it seems like Firefox does not allow me to open the ctrl-f field to type text. I want to use this on image pages, because there are times when I need to retrieve information from an image, like the title of a book from the image of a book cover, and it is much more convenient to type out the text in the same window (alternatives would be something like writing out the text on a piece of paper and then typing it after leaving the tab, or opening some other program where I can type text, or trying to memorize the text). If I type out the text in the url field it usually shows a bunch of dropdown text that covers the image and keeps me from being able to see what I'm typing, which is why I usually use the ctrl f field to type. Is there a setting I can change that would allow me to use ctrl-f on pages that only have an image? edit: the best alternative I can find is to open web developer tools in the page and use the ctrl f field within the web developer tools window