When you are attempting to upload a document to a rigid government web portal or a legacy corporate database, you will frequently encounter systems that violently reject PDF files and explicitly demand JPEG or PNG image uploads. If you have a massive, 20-page PDF document, you do not need to download third-party conversion software or take messy, low-resolution screenshots of your screen. The built-in macOS Preview application contains a highly robust export engine that can instantly convert any PDF document into a series of pristine, high-resolution JPEG images.
How to Convert a PDF to JPEG
Because PDF is a vector-based format (meaning the text is mathematically drawn) and JPEG is a raster format (meaning the image is built from thousands of static colored pixels), this process requires Preview to physically “render” the document.
- Double-click the PDF file to open it in Preview.
- Look at the main menu bar at the top of your Mac screen and click File.
- From the drop-down menu, select Export. (Do not select “Export as PDF”).
- A save dialog box will appear. Look at the bottom half of the window and click the Format drop-down menu.
- Change the format from PDF to JPEG.
Adjusting Export Resolution and Quality
Once you select JPEG as the export format, two new sliders will instantly appear in the dialog box: Quality and Resolution.
- Quality: Dragging this slider to “Best” guarantees that the resulting JPEG will not suffer from ugly, blocky compression artifacts, but it will significantly increase the final file size.
- Resolution: This is the most critical setting. By default, Preview might try to export the image at a low 72 pixels/inch (which looks terrible if you try to print it). For a crisp, professional document, you must manually change the Resolution box to 300 pixels/inch.
Once your settings are dialed in, click the Save button. Preview will instantly render the PDF and drop a high-resolution JPEG file onto your hard drive.
How to Export Multiple Pages
The standard Export menu will only convert the specific page you are currently viewing. If you have a 5-page PDF and need to convert every single page into 5 individual JPEG files simultaneously, you must use a slightly different workflow.
- Open the PDF in Preview.
- Ensure the sidebar is visible by clicking the View menu and selecting Thumbnails.
- In the left-hand sidebar, click on a thumbnail, then press Command + A to highlight every single page in the document.
- Click File, but this time select Export Selected Images.
Choose your destination folder and click Save. Preview will instantly slice the PDF apart, convert all 5 pages simultaneously, and dump 5 perfectly numbered JPEG files directly into the folder.