Illustrator 2026 embeds each duplicate bitmap image separately in PDFs, causing extremely large files
Mac Studio M2 Ultra, Tahoe 26.5.1
Illustrator 2026 embeds duplicate instances of the same bitmap separately when saving a PDF, causing the PDF size to increase with every duplicate.
To test this, I used one 2000 × 2000 PNG file that is 7.5 MB. I placed it once, duplicated the placed object a total of 9 times, and saved the same layout as a PDF using comparable settings in Illustrator 2025, Illustrator 2026, and InDesign 2026.
Results:
Illustrator 2025 version 29.8, Adobe PDF Library 17: 8 MB
Illustrator 2026 version 30.3, Adobe PDF Library 18: 71 MB
InDesign 2026 version 21.4, Adobe PDF Library 18: 7.9 MB
Illustrator 2025 and InDesign 2026 appear to embed the bitmap once and reuse it for the duplicate placements. Illustrator 2026 appears to embed the bitmap data separately for each duplicate instance.
The InDesign result shows that Adobe PDF Library 18 can produce an efficient PDF from the same duplicated bitmap layout. This points to a regression in Illustrator 2026 or Illustrator 2026’s integration with PDF Library 18, rather than a general limitation of PDF Library 18.
Expected result: Illustrator should embed each unique bitmap once and reference that image for all duplicate placements, as Illustrator 2025 does.
Actual result: Illustrator 2026 creates a PDF many times larger because each duplicate bitmap instance appears to be embedded separately.
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This happens with any bitmap image regardless of the file format.
I used the Default PDF Preset with "Standard:None", and Compatibility: Acrobat 7(PDF1,6)" in both versions of Illustrator. I have tried all the different Standards (PDF/X-***) and the file size only changes slightly due to the Compression settings changing.
The Compression is Zip and set to not downsample.
XMP asset manifest in both PDFs identifies only one source bitmap, using the same Photoshop document ID and instance ID. So Illustrator 2026 still knows that all nine placements originated from the same embedded image. It simply doesn't reuse that image when constructing the PDF.
I tired to upload the files here but either something is wrong with the uploader or the file size that can be uploaded is tiny.
I put some smaller test files that I have been using in here:
drive.google.com/drive/folders/1Q4O-4C7ViGEkQ_qEVXOs_KSlg84IYJTO?usp=sharing -
Not seeing this when I try to replicate it.
I grabbed a PNG with noise, 3000×3000, 8.58 MB.
I tested this in the latest GA 30.6, Beta 30.8, older versions 21 and 28.
In all 4 I made 30 copies, and saved using the [Illustrator Default] preset.
I got similar file sizes of 9 MB (ranging 9227-9249 KB).
If I use PDF/X-4 instead, I get 0.8-1.16 range instead.
Please tell more:
— Which preset / settings were you using, meaning 'comparable settings'?
— Does it happen with any PNG placed?
— If only the specific PND does it — can you share it?
