The built-in tools to do various conversion tasks are not obvious or intuitive, and often require a web lookup to figure out. Yes, even on macs.<p>Concatenating images or pdf's into a pdf MAY be doable with built-ins, but I got an app off the app store to do it. A n00b probably couldn't figure either, and might use an online tool.<p>Consider downloading or linking a webp file. One site I use won't render webp. So on the iphone, I save it to photos then files, because the photo app will NOT convert files, and online images CANNOT be saved to the files app. Next, go to the files app, hold my finger down on its thumbnail (DO NOT open it), and select quick actions - convert image.<p>WAIT, there's more.<p>Open the new converted image, and "save" to the photos app.<p>And THEN upload it to a photo hosting site.<p>GOT IT? No wonder people use online dodgy tools.<p>FWIW, this is much easier on a desktop or laptop, but the steps are not intuitive to the non tech-savvy user, the target of exploiters.