JPG to PDF: Choose Compression and Check Text Clarity
A PDF is a container, not an automatic photo compressor. Several large phone photos can remain large when placed on PDF pages. Making the displayed page smaller does not necessarily remove image pixels. PDFFlow offers image quality settings during JPG-to-PDF conversion so you can balance attachment size against the detail you need.
1. Start with the submission requirement
Check the receiving website for a maximum file size, page count, accepted format, and required paper size before converting. These are different requirements: a smaller file can still have the wrong page dimensions. PDFFlow creates a page for each image and preserves its proportions. It does not turn every image into an A4 or US Letter page. Keep original photos so you can retry with more detail if a receiving office rejects the result.
2. Choose a quality setting for your document
Balanced is the default for ordinary documents. Small file prioritizes attachment size; High quality keeps more detail for small print or later OCR. Original embeds image data without image compression and may produce a much larger PDF. Compressed modes reduce oversized images and encode them as JPEG. Transparent PNG regions become white in those modes, while Original preserves transparency. A diagram with fine lines may need High quality or Original even when a normal photo looks good at Balanced. A scan that must be printed at an exact physical size needs a separate page-size check; these quality choices control image detail, not an A4 or Letter layout.
3. Why there is no guaranteed compression percentage
Results depend on the source. Large photos with more pixels than you need often have room for reduction. A JPEG that is already optimized may shrink little, and the PDF container adds its own overhead. Repeatedly converting PDF to JPG and back can reduce detail without a useful size saving. Work from the original images when trying another quality setting, and compare the downloaded file size rather than assuming that every conversion will be smaller.
4. Check the details that matter
Arrange the photos in the intended order, choose a setting, convert, and open the downloaded PDF. Compare the smallest text, stamps, dates, and receipt totals with the source. Check the page at normal reading size, then zoom in around thin strokes. If text is smeared or punctuation disappears, move to a higher-quality setting. If the file remains too large, remove unnecessary pages only when the recipient allows it, or ask whether separate attachments are accepted.
5. Prepare for OCR without confusing it with compression
An image-only PDF still contains pictures of words, even when those words look sharp. JPG-to-PDF conversion does not create searchable or editable text. For Word output, open the PDF in PDF to Word and choose English or English + Korean for OCR. Keep small text clear before that step; increasing the resolution of an already blurred image cannot recover missing details. Read the OCR result against the source, especially amounts and reference numbers.
6. Handle browser limits
The converter accepts up to 50 images, 150 MB in total, and 40 megapixels per image. These are input limits, not a promise that every device can process the maximum. Decoding an image uses more memory than its compressed file size suggests. If a mobile tab reloads or fails, use fewer images in each batch or a device with more available memory. Do not close or refresh the tab until the output is ready.
💡Illustrative workflow
For a receipt submission, start with Balanced, arrange receipts by date, and compare the exported size with the portal limit. Inspect the faintest receipt and the smallest totals. If they are difficult to read, retry from the original images at High quality.
⚠️Important Guidelines & Caveats
Compression can discard image detail. This tool creates a PDF from JPG, JPEG, and PNG images; it is not a general compressor for an existing PDF and does not add an OCR text layer.
❓Frequently Asked Questions (FAQ)
Q. Can I guarantee a result below 1 MB or 5 MB?
A. No fixed output size is guaranteed. Image count, detail, dimensions, and chosen quality affect the result. Check the actual exported size against your destination limit.
Q. Does a smaller PDF automatically remain good for OCR?
A. No. OCR needs distinguishable character strokes. Use High quality for small print and compare the recognized text with the original. Good lighting and a sharp source matter as well.
Q. What image formats are supported?
A. JPG, JPEG, and PNG. Convert other formats to a supported image format first; do not rename an extension and expect the image format to change.
About this guide
This article is maintained against the tools currently available on PDFFlow. Browser and PDF features vary, so preserve the original document and inspect the downloaded result before formal submission.