Use GIMP to convert format of an image (including one page PDF)
Chinese version: Zhihu Step 1: File -- Open, open an image. (If it is a one page PDF file, click Import directly.) Step 2: File -- Export as, change the file extenstion to what you want and the destination folder, then click Export. I tried that this function can convert one page pdf to jpg, you can try to convert multiple pages pdf by yourself.