Converting JPG·PNG photos to PDF: How to set steps, A4 margin, and image quality

Order of combining multiple photos into one PDF

1. Select JPG·PNG·WebP files in the image to PDF conversion tool.
2. Use the up and down buttons to determine the order of images to be included in the document.
3. Select paper size, orientation, and margins.
4. If you mainly focus on photos, compare JPEG output, and if you want to avoid compression traces of text or lines, compare PNG output.
5. Click Create PDF, see the batch preview, and download the PDF.

One image becomes one page. There are no features for gridding multiple photos on one page or automatically cropping the original image. If the file selection order is different than expected, change the order in the list on the screen.

A4·Letter·Image ratio and margin selection

A4 is 210×297mm, Letter is 8.5×11 inches. Auto Orientation selects landscape paper if the image is horizontal, otherwise selects portrait paper. You can also specify height and width directly. The image is centered to fit within the margins, maintaining its proportions, so if the image and paper ratios are different, empty space is left.

Select the margin from 0·10·20mm. After processing the image ratio paper, 96 pixels of the image are converted to 1 inch and margins on both sides are added to determine the page size. This is not how the print resolution metadata of the original file is read. Direction selection does not apply in this mode.

Difference between JPEG quality 85 and PNG, long side 2048·4096px

The JPEG save is lossy compression, passing a quality value of 0.85 to the browser encoder. Quality 85 does not guarantee 85% preservation of original image quality or 15% reduction in file size. Fill the transparent parts with white. PNG stores processed pixels losslessly, but does not copy the original image file or metadata.

Long side limit is 2048px or 4096px. Large images will be scaled down to fit the limit, and small images will not have their pixel count increased. 4096px may be helpful for viewing small text or zooming in, but may increase memory and result capacity. Even if you choose PNG, the reduction process may reduce detail in the original. Enlarge the downloaded PDF to its actual size.

Text search and size limitations in photo PDFs

Even if you insert a photo into a PDF, the text in the photo does not turn into selectable text. This tool does not provide OCR. If a document needs to be searched or copied, it must be exported from the original text document to PDF or require separate OCR processing.

Up to 20 images, 20MiB per file, 100MiB in total, and each image must be within 16 million pixels and 8192px on each side. Output PDF is limited to 150MiB or less. If it fails on large files, reduce the number of images or long sides. Just binding to PDF does not reduce the size.

Technical Notes: pdf-lib JPEG insertion, Insert PNG, MDN Canvas image encoding.

Frequently Asked Questions