Compress Medical Records PDF Files on a Mac, Before You Send

There is no common limit: each portal sets its own, and the three portals below differ by a factor of almost 30. Look for the number on your own portal’s help page before you pick a preset, because the right target is the receiver’s cap, not a general rule.

Two lessons follow. A 3.5 MB cap is easy to exceed with a multi-page color scan, so expect to compress. And fax and email limits count pages or encoded bytes in ways that make “just under the cap” risky: our guide to getting a PDF under Gmail’s 25 MB limit measured email encoding at roughly 37% overhead, so a 25 MB cap means aiming near 18 MB.

Open Smol, drop the PDF in, choose a preset and compress. The presets are Tiny, Small, Medium, Large and Original, and the result is saved as a copy beside the original with a _compressed suffix. Check the size of the copy against the cap before you send.

The presets are long-edge pixel caps, not DPI targets: 600, 900, 1200, 1800 and 2400 px for Tiny, Small, Medium, Large and Original, with JPEG quality of roughly 25, 45, 60, 75 and 88. A letter page capped at 1200 px on its long edge lands well below 300 PPI, so the preset decides how crisp small print stays. Original is not lossless: it re-encodes and resamples anything above 2,400 px. The full explanation is in what the PDF presets actually do.

A scan stores each page as a picture, and a letter page at 300 PPI in color is 2,550 × 3,300 pixels. In our test, a 3-page, 300 PPI color scan of an agreement weighed 5,017,560 bytes, over 1.6 MB a page, before any compression.

Three choices at the scanner shrink a chart before Smol touches it: scan at 200 to 300 PPI rather than higher, scan black-and-white for typed text, and avoid saving each page as a separate TIFF. Then compress. Preset choice matters for searchability. In the scanned-PDF test, a Tesseract OCR pass recovered 100% of words at Medium (109 PPI), 96.8% at Small (82 PPI) and only 1.42% at Tiny (55 PPI). That tells you Tiny is the wrong choice for a chart someone must read or search.

Smol does not run OCR. In that post, a separate tool (OCRmyPDF) added the text layer and Smol’s Medium preset then took the scan from 5,017,560 to 288,609 bytes with the text intact. If your scanner or records software already adds a text layer, test that the copy still searches after compression.

Imaging software can export an x-ray as an image file, and the sizes vary with sensor and settings, so there is no standard figure to quote. Smol compresses those exports to JPG, PNG, WebP, AVIF or HEIC at a quality you choose, and it can resize to a maximum width or height.

Compression of images is lossy: Smol has no lossless mode, so every output is re-encoded. Whether a smaller export is acceptable for diagnosis or for the receiving office is a clinical decision, not something Smol can tell you, so keep the original export and send the copy only where the receiver agrees. For a portal that wants JPG or PDF, as the Peace Corps portal does for .jpg, .jpeg and .pdf, compress with output JPG.

Image defaults to know: quality starts at 75, metadata is stripped, and images are resized to fit inside 2000 × 2000 px unless you change it. Raise or switch off that resize if the receiver needs the full pixel dimensions. The benchmark measured 69.3% smaller high-quality JPEGs at default settings, on 24 small 768 × 512 photographs; your exports will land differently.

Start with Small for anything going by email or fax and Medium for scans that must stay readable, then adjust after reading the output size. The quality numbers below are starting points we chose, not guarantees of a file size.

A note on metadata

Image compression strips EXIF, GPS, IPTC and XMP by default, and the separate strip-metadata operation can do the same for PDFs and images. Stripping clears properties such as author and title fields. It does not remove a name printed on the page itself, and for PDFs the result can be reversed with a free tool unless the file is rewritten afterward, as our PDF metadata guide explains. Smol does not redact anything on the page.

Drop the whole folder into Smol and run one job: mixed PDFs and images go in together and each file shows its own progress and savings. The workflow below is the one to repeat.

1. 1

   Copy the records to a working folder

   Originals are untouched by default, but a working copy keeps the chart folder clean.
2. 2

   Drag the files or the folder into Smol

   Mix PDFs and image exports in one batch. See batch compressing PDFs on Mac for the details.
3. 3

   Choose Small or Medium for PDFs; JPG at quality 80 for images

   Save the choice as a preset. Presets live on one Mac, so write the settings down for others.
4. 4

   Compress, then open the largest output

   Look at the page, zoom into small print, and read the size against the receiver’s cap.
5. 5

   Send the _compressed copies

   If a file is still over, step down one preset and run it again from the original.

Free and built-in options come first. Preview’s Reduce File Size is built into every Mac, and it can make text PDFs bigger: in our test a 21-page text-only contract grew by 111.8% (details here). The scanner software, a print-to-PDF option and online tools are the other common routes.

The comparison that decides it is where the file travels. An online compressor receives the record on its own server; Smol compresses on your Mac and uploads nothing. We make no statement about which your office’s policies allow. See Adobe Acrobat alternatives for Mac and the best PDF compressor for Mac for tested figures.

Smol is not the right choice for every record workflow. Use something else when:

• The files are DICOM studies. Smol does not read DICOM; export an image from your imaging system first.
• You need to redact, sign, merge or split a PDF, or add searchable text. Smol does none of these, and it has no OCR.
• You need identical pixels. Smol always re-encodes images; a lossless optimizer is the better fit, as in our ImageOptim comparison.
• Your staff use Windows or iPads. Smol runs on macOS only.
• The record is a text-based PDF from your EHR. It may compress by almost nothing, so ask the system for a smaller export.

For a small office, a Team license ($49) covers three Macs and Enterprise is $20 a seat from 5 seats. Compare against the policy of your practice, which we cannot advise on. Also see the law firm PDF filing and confidential documents pages for related workflows.