Turning PDF pages into JPGs is the usual move when you need to drop a page into a slideshow, paste it into a chat, or post it somewhere that only accepts images rather than documents. Multi-page PDFs are converted page-by-page, giving you one JPG per page, rendered directly from the PDF's content so text stays sharp rather than looking screenshotted.
Rendering a page rather than pulling out pictures
There are two different things people mean by getting images out of a PDF. One is extracting the photographs that were embedded in it. The other, which is what happens here, is rendering each page as it would appear on screen or in print, and saving that rendering as an image.
So the output is one picture per page, complete with its text, tables, headers and whatever illustrations sat on it, laid out exactly as the document defines. If your PDF is a scanned contract, the result is a picture of that contract. If it is a designed report, you get the design.
Text becomes pixels, and stays that way
In the source document text is stored as characters plus a reference to a font. Once a page is rendered, those characters are gone and what remains is the shapes they happened to make. The result cannot be searched, selected, copied or reflowed, and a screen reader has nothing to announce.
That is sometimes the entire point, as when you want a page pasted into a slide deck or a chat message where it will simply be looked at. When it is not the point, it is a genuine loss and worth avoiding: to pull out a subset of pages while keeping them as documents, split the PDF instead. If you have gone the other way and need the words back out of an image, the OCR tool will read them, though it is reconstructing text rather than recovering it.