A free app for Android, by BG.Studio.

Image to PDF – PDF converter is a free application that lets you quickly convert your images into PDFs. The resulting PDFs are compatible with any device and can be viewed on both desktop and mobile devices. You can easily edit and improve the quality of your PDFs, and they can be shared via email, Facebook, Twitter, and other social media.

Image to PDF supports a wide variety of image formats. It includes small tool to crop and edit photo before converting PNG/JPEG file to PDF document.

To get started, simply open the app, choose the desired image format, select a folder to save your files to, and tap Convert.