Convert PNG to PDF on Mac

Design handoffs arrive as twelve PNG screens. The client portal accepts one PDF, not a zip of images. Insurance scans from a phone may be PNG when the camera saves lossless stills. One merged PDF fixes page order, satisfies single-file upload fields, and prints cleanly. PNG pages keep sharp text; merging does not shrink them. Plan a compression pass after export when email or portals cap megabytes.

Retina PNG mockups at 3000 px wide can produce a 30 MB PDF that Gmail rejects. Cap width before merge when the destination is screen-only.

When one PDF beats many PNG files

Scenario	Why merge into PDF
Client portal	Single upload field
Print shop	Fixed page sequence
Legal packet	Signatures on correct pages
Email	One attachment vs many

Each PNG carries full raster data. A folder of Retina mockups can produce a 30 MB PDF that Gmail rejects. Resize PNG width before merge when the destination is screen-only.

If you need the reverse, see PDF to images on Mac or PDF to PNG on Mac for page exports. For JPEG scans instead of PNG, see JPG to PDF on Mac .

Mistake to avoid	Why
Full-res merge for screen review	Huge PDF that upload rejects
Wrong page order	Client confusion on review
Skipping zoom check on text	Illegible signatures go live

Combine PNG files in Preview

Preview is the built-in way to convert PNG to PDF on Mac:

1. Open the first PNG in Preview.
2. Choose View → Thumbnails.
3. Drag other PNG files into the sidebar. Each image becomes one page.
4. Choose File → Export as PDF… and save.

Batch tip: select multiple PNG files in Finder, open together in Preview, and they load as pages in one window.

Step	Why it matters
Thumbnail reorder	Fixes screen flow before export
Tools → Rotate	Corrects phone scans
Edit → Insert → Blank Page	Separates sections

Preview preserves PNG sharpness better than re-saving through lossy steps. Export PDF once, then compress if needed.

Use zero-padded names (page-01.png) so thumbnail order matches screen flow when you open multiple files at once.

Transparency and page size

PNG transparency becomes white or checkerboard in some PDF viewers depending on export path. Flatten in your design tool when the background must be a brand color on every page.

Goal	Preview step
Uniform width	Tools → Adjust Size before merge
Screen handoff	Cap width near 1920 px
Print	Keep source resolution

Oversized PNG mockups at 3000 px wide produce oversized PDF pages. Resize in Preview before Export as PDF when reviewers view on screen only.

For PNG to JPEG before merge when file size dominates, see PNG to JPG on Mac . Sometimes JPEG pages yield smaller PDF files for photo-heavy scans at the cost of transparency.

Use FFmpeg to resize PNG inputs before merge when you already batch with scripts:

mkdir resized
for f in *.png; do
  ffmpeg -i "$f" -vf scale=1920:-2 "resized/${f%.png}.png"
done

Merge the resized/ folder in Preview afterward.

Shrink the PDF after merge

1. Open the PDF in Preview.
2. File → Export…
3. Quartz Filter → Reduce File Size
4. Save as a new file and check text at 100% zoom.

If quality drops too much, resize PNG sources first instead of crushing the merged PDF.

See how to compress PDF on Mac for portal limits and second-pass options.

Spot-check one UI screen with small type after Reduce File Size. Thin fonts show artifacts before photos do.

Symptom	Fix
PDF still too large	Resize PNG sources first
Text looks soft	Avoid crushing PDF twice
Wrong page order	Reorder thumbnails and re-export

Compare file size before email. A 28 MB merged PDF from full-res mockups needs a resize pass, not just retry upload.

Using GetCompress

GetCompress does not merge PNG into PDF. Use Preview for merge first. After export, GetCompress shrinks the PDF when attachment limits still fail.

• Drop merged PDF into GetCompress with a PDF preset.
• Preview signature and small text pages before batch upload.
• Batch several merged PDF files for recurring client submissions.
• Save presets for expense or design review packets.
• Process locally when mockups are under NDA.

For image cleanup before merge, see how to compress images on Mac to cap PNG width in the source folder.

GetCompress does not merge PNG into PDF. Use Preview first, then GetCompress when the merged file still exceeds portal limits. When a portal rejects the first upload, tweak the PDF preset once rather than re-exporting from full-res PNG unless the mockups changed.

Keep full-resolution PNG sources on project storage. Write compressed PDF deliverables to a separate folder so you can re-merge at higher quality if a client requests it later.