Image formats
Image formats for PDF: JPG, PNG, TIFF and HEIC compared
By DeckleUpdated
JPG suits photos, PNG suits screenshots, diagrams and anything with text, TIFF is the usual format for scanned documents, and HEIC is what iPhones save photos in. Deckle converts all four to PDF, each with its own tool: JPG to PDF, PNG to PDF, TIFF to PDF and HEIC to PDF. The best format for a PDF page is usually the one the image is already in.
Choose a source for the job
Photograph
Inspect colour and detail
Diagram
Inspect lines and labels
Scan
Inspect frames and text
A static PDF page does not preserve motion
Find the right guide
| Your question | Read |
|---|---|
| Why does my JPG make text look fuzzy? | Why JPG makes text blurry |
| Should diagrams be PNG or JPG? | PNG vs JPG for diagrams and line art |
| What happens to a transparent background? | PNG transparency in PDF |
| Should I scan to PNG or TIFF? | PNG vs TIFF for scanned documents |
| Should I keep scans as TIFF or PDF? | TIFF vs PDF for scanned documents |
| HEIC or JPG for sending photos? | HEIC vs JPG for sharing |
| Can a Live Photo become a PDF? | How to convert a Live Photo to PDF |
For step-by-step conversion guides, see images to PDF.
The four formats at a glance
| Format | Compression | Transparency | Several pages in one file | Best for |
|---|---|---|---|---|
| JPG / JPEG | Lossy | No | No | Photos |
| PNG | Lossless | Yes | No | Screenshots, diagrams, logos, text |
| TIFF | Usually lossless | Sometimes | Yes | Scans, archives, print work |
| HEIC / HEIF | Lossy, efficient | Possible | Possible | iPhone and iPad photos |
Lossy means the format throws away detail to save space; each save loses a little more. Lossless means every pixel is kept exactly. Apple's Photos app describes TIFF and PNG as lossless and JPEG as creating small files suitable for websites (Export photos on Mac).
What each format becomes inside a Deckle PDF
The image tools treat each format differently on the way in:
- JPG to PDF copies the JPEG into the PDF byte for byte. Nothing is re-compressed, so the photo keeps its exact quality, and EXIF data such as GPS location comes with it. A photo over the device's pixel limit is the exception: it is scaled down and re-saved at quality 90, without its EXIF data.
- PNG to PDF keeps every pixel and stores it with lossless compression. Transparency is kept, even when a PNG over the limit is scaled down.
- HEIC to PDF decodes the photo and saves it as a JPEG at quality 90, because a PDF cannot hold HEIC data. Camera and location metadata are left out.
- TIFF to PDF decodes every frame and saves each as a quality-90 JPEG on a white background, one page per frame. TIFF tags are left out.
In all four, each image or frame becomes one page, and page size comes from the image's pixels or from Fit inside A4, never from its DPI tag. How images become pages in a PDF covers the page model.
Choosing a format before you make the image
If you control how the image is created, these choices give the best PDF:
| You are making | Save as | Then use |
|---|---|---|
| A photo | JPG (or HEIC on iPhone) | JPG to PDF or HEIC to PDF |
| A screenshot | PNG | PNG to PDF |
| A chart, diagram or logo | PNG | PNG to PDF |
| A scan of a multi-page document | PDF directly, or TIFF | TIFF to PDF if you have TIFF |
| A scan of one page | PNG or TIFF | The matching tool |
If the image already exists, keep its format. Converting a JPG to PNG gains nothing, and converting a PNG to JPG adds blur around text.
Formats Deckle does not convert
WebP, GIF, BMP and AVIF are not accepted by any of the image tools. Open them in an image editor and save as PNG for graphics or JPG for photos. Within the supported formats, a few variants are refused: animated, interlaced and 16-bit PNGs; HEIC files holding several images; and TIFFs with fax (CCITT), PackBits or JPEG compression, or CMYK colour. Each page keeps up to 16 megapixels on a computer or Android device, and 4 megapixels on iPhone and iPad; a larger image is scaled down to fit. Images above 64 megapixels, or 25 megapixels on iPhone and iPad, are refused before you start.
Frequently asked questions
Which image format is best for a PDF?
The one your image is already in. JPG to PDF and PNG to PDF do not re-compress, so the PDF matches the source exactly.
Is PNG better quality than JPG?
PNG is lossless and keeps sharp edges perfectly, which matters for text and diagrams. For photos, a good JPG looks the same and is much smaller.
Why does HEIC become JPEG inside the PDF?
PDF has no way to store HEIC data, so the photo is decoded and saved as a high-quality JPEG.
Can one image file hold several PDF pages?
Yes, a multi-page TIFF. Each of its frames becomes a page.
Related tools
- JPG to PDF for photos
- PNG to PDF for screenshots and diagrams
- TIFF to PDF for scans
- HEIC to PDF for iPhone photos