I very much agree with Dave Salyer‘s point of view. Converting JPG to PDF via the built-in software- Preview (Mac) and Print Pictures (Windows）is the most secured and free way. Actually, there is also another quick and free way- using an online JPG to PDF converter. PDFfiller should be the leader in this field. Besides converting JPG, it allows you to convert BMP, TIFF, GIF, PNG, Excel, PPT, etc. to or from PDF as well. You can convert all the files that even are stored in your Dropbox or Google Drive. Step 1. Go to PDFfiller website and choose “JPG to PDF”. Step 2. Click “CHOOSE FILES” to add JPG files you want to convert. Step 3. Start create PDF file and download it. Of course, you can install a professional PDF converter like Cisdem PDF Converter OCR to convert PDF from or to 16+ formats including image (JPG, PNG, BMP, etc.) , Word, Pages, Text, Html, Excel, etc. without losing formatting and quality.
When PDF is an object in the file manager, and you want the PDF to be a file, you put it into that container object, and you get a file from the PDF (or you don’t, of course, but it's a way around the object that saves space and keeps the file sizes down). You then use the file's properties to change its properties from its original file-like state. For example, you can change the font (to make the PDF look nicer), or the text size. If you change the text size, it will not be displayed like a typical image, the pixels will look all messed up and your PDF will get a bit more “realistic”. Then, in the object properties, it can be changed to have this effect by changing the properties under the “Image” option. It has saved a lot of time in my.