You export a PDF and the images look noticeably worse than in the original document — blurry, pixelated, or showing JPEG compression artifacts. This happens because of how the images were embedded during the export process, not because the images themselves were damaged. The problem is almost always fixable by adjusting export settings or the image preparation workflow.
Cause 1: Low-Quality PDF Export Settings
The most common cause: the PDF was exported with settings that downsample images to a low resolution or apply heavy JPEG compression. Microsoft Word's "Minimum size" export option, for example, reduces images to 96 DPI — appropriate for web display but poor for print or detailed screen viewing. The same document exported with "Standard" or "High quality print" settings produces dramatically better image quality.
The fix: re-export from the source document using higher quality settings. In Word, File > Save As > PDF, click Options, and change the optimization from "Minimum size" to "Standard." In PowerPoint, File > Export > Create PDF/XPS, click Options, and select a higher quality preset. In most applications, look for "print quality" or "high quality" export options rather than web or screen optimized settings.
Cause 2: Images Were Already Low Resolution Before Export
If the source images were low resolution — downloaded from a website at 72 DPI, taken as screenshots, or captured at a low quality setting — the PDF export faithfully preserves that low quality. Exporting at maximum PDF Quality settings can't add detail that wasn't in the original image.
Diagnose this by checking the image in the source document: right-click the image in Word or PowerPoint and look at its properties or size information. A photo that's displayed at a large size but was originally a small file — say, a 500×400 pixel image displayed at full page width — will always look pixelated. The solution is to replace the image with a higher-resolution version before exporting.
Cause 3: Word's Image Compression Setting
Microsoft Word compresses images by default when you save a document — this reduces the .docx file size but also permanently reduces the embedded image quality. By the time you export to PDF, the images in the Word file are already compressed versions of the originals.
To disable this: in Word, go to File > Options > Advanced, scroll down to Image Size and Quality, check "Do not compress images in file," and save the document. For images already compressed, this setting doesn't restore lost quality — you'd need to reinsert the original images. For future documents, disabling compression before inserting images prevents the problem.
Alternatively, use the Compress Pictures option (Picture Format > Compress Pictures) and select "Do not compress" or choose a higher resolution target before exporting. Setting the resolution to 220 PPI for print output produces images suitable for most print and screen uses.
Cause 4: PDF Compression Applied After Export
If the PDF was exported at good quality but then compressed to reduce file size, the compression may have degraded images beyond an acceptable threshold. Heavy PDF Compression — particularly maximum compression settings — applies aggressive JPEG compression to images, causing visible artifacts and softness.
The original uncompressed export is the reference — if you kept it, recompress at a lower setting. Medium compression typically maintains acceptable image quality for screen and standard print. If the original export wasn't saved and the compressed version is all you have, re-export from the source document and compress more conservatively this time.
Cause 5: Print-to-PDF Instead of Native Export
Printing to PDF (File > Print > Save as PDF or Microsoft Print to PDF) processes the document through a print driver at screen resolution rather than using the native PDF export engine. The result is a PDF where images are rasterized at screen DPI — typically 96 DPI — rather than embedded at their original resolution.
Always use the application's native PDF export (File > Save As > PDF, File > Export > PDF) rather than Print to PDF when image quality matters. Native export embeds images at their original resolution; print-to-PDF rasterizes everything at screen resolution.
Checking Image Quality in the Exported PDF
After re-exporting, zoom to 150% and inspect each important image. For print-intended documents, images should look sharp at 150% zoom — this approximates how they'll look when printed at standard size. For screen-only documents, 100% zoom is the relevant test. In Adobe Acrobat Pro, go to File > Properties > Description to see the document's resolution settings, or use Tools > Print Production > Output Preview to examine individual image resolution and color data.