PDF or JPG: which format should you send a document in?
By the PdfDady team · Updated · 8 min read
Send a PDF when the thing is a document: anything with more than one page, anything someone will print, anything with text they need to read closely. Send a JPG when the thing is a picture: your photo, your signature, a single snapshot of a card.
And when a form tells you which format to use, the form wins. Upload fields are often strict. A field that asks for PDF won't take a JPG, and a photo field that asks for JPG won't take a PDF.
Changing one into the other takes a minute. Our Image to PDF tool turns photos into one PDF, and PDF to JPG goes the other way. Both work in your browser without uploading the file.
What each format is
A JPG is one picture. It is a grid of pixels, compressed to keep the file small. It has no pages, no text you can select, and no fixed paper size.
A PDF is a container for pages. Each page has a real size, such as A4, and can hold text, drawings and pictures together. A PDF made by software (a bank statement, an e-ticket) holds real text. A PDF made from photos holds those photos, one per page.
That second point clears up a common belief. Putting a photo inside a PDF doesn't improve it or make it "more official". It is the same picture on a page. What you gain is the page: a fixed size, a fixed order and one file in place of several.
| JPG | ||
|---|---|---|
| Pages | Many, in a fixed order | One image per file |
| Prints at a set size | Yes, the page size is stored | Depends on the print settings |
| Text | Can be real, selectable text | Always pixels |
| Password | Can be protected with one | No |
| Opens in a gallery app | No, needs a PDF viewer | Yes |
| Typical use | Certificates, statements, forms, multi-page scans | Photo, signature, a single ID image |
For online application forms
Most forms split their uploads into two kinds, and the format follows the kind.
Photo and signature fields nearly always want an image, with a size limit in KB and often pixel dimensions too. Use JPG unless the notice says otherwise.
Supporting document fields (marksheets, caste or income certificates, ID proof, address proof) usually want a PDF, with a limit in KB or MB.
The exact formats and limits are in the form's notice or on the upload page. They differ between exams and change from year to year, so read them each time instead of relying on what last year's form wanted.
Official guidance, where it exists, leans the same way for documents. The Income Tax Department's advice for attachments is to scan to PDF, at 300 DPI, in black and white, and not to upload password-protected files.
If your documents are photos on your phone and the form wants a PDF, combine them with Image to PDF. You can add up to 50 images (JPG, PNG, WebP or iPhone HEIC), put them in order, and choose A4. If the PDF is then over the limit, bring it down with Compress PDF.
For email
PDF, almost always. One attachment, in the right order, that looks the same on every device and prints properly. Six loose JPGs named IMG_2041.jpg to IMG_2046.jpg leave the other person to work out which is which.
Size matters here too. Personal Gmail accounts can send attachments of up to 25 MB, and Gmail turns anything bigger into a Google Drive link. Your recipient's mailbox or office mail server may accept less, so for a job application or an office email, keep it to a few MB if you can.
One thing a PDF can do that a JPG can't: carry a password. If you are emailing a salary slip or an ID copy, you can add one with Protect PDF and send the password separately.
For WhatsApp
Here the question is less PDF vs JPG than how you attach it.
A picture sent as a photo, through the gallery or camera button, is shared at the quality WhatsApp sets. Its help pages describe a choice between standard and HD quality for photos you attach. Standard quality is fine for reading a message. It can make the small print on an ID card or a marksheet hard to read when the other person zooms in or prints it.
Anything sent through the Document option goes as a file. WhatsApp allows documents of up to 2 GB.
So for anything that has to stay legible:
- Send it as a PDF, attached as a document. This is the dependable choice for certificates, bills and ID copies.
- If it must be an image, attach the JPG as a document as well, or choose HD quality before sending.
A PDF also keeps a multi-page document together. Ten photos sent in a chat arrive in a pile and get saved to the gallery among everything else.
What happens to quality when you convert
Photos to PDF. With our tool, a JPG that needs no rotation is placed in the PDF with its original image data, not re-compressed, and PNGs stay lossless. So the PDF is about the size of the photos you put in. It is not automatically smaller. Five phone photos of 3 MB each make a PDF of around 15 MB.
PDF to JPG. Each page is drawn as an image at the resolution you pick: 72, 150 or 300 DPI in PDF to JPG. The text becomes pixels and can no longer be selected or searched. A page that was crisp typed text in the PDF will be a little softer as a JPG, and going back to PDF later won't restore the text.
That last point is the main reason not to convert back and forth casually. If you have a real text PDF, such as a downloaded statement or e-Aadhaar, keep it as a PDF for as long as you can. Convert to an image only when the destination demands one. More on formats and DPI is in our guide on converting a PDF to JPG or PNG.
A privacy point about phone photos
Photos from a phone camera can carry hidden details, including the GPS location where the picture was taken. Send the original JPG as a file and that information can travel with it.
When you build a PDF with our Image to PDF tool, location data (EXIF/GPS) is removed from the JPEGs placed in it. If you photographed your documents at home, that is a quiet advantage of sending the PDF.
Common mistakes
Sending a photo of a document with the desk around it. Image to PDF doesn't crop, so frame the document closely when you take the picture. If you need the corners straightened and the background cleaned up, Scan to PDF is made for that.
Renaming the file to change its format. Changing aadhaar.jpg to aadhaar.pdf doesn't convert anything. The file is still a JPG with a wrong name, and a portal or a viewer may fail to open it. Convert it properly.
Uploading a huge PDF made from full-size photos. Check the size before you submit. Our guide on reducing PDF size for upload explains how to fit a limit.
Converting a text PDF to JPG "to be safe". You lose the selectable text and usually gain nothing, unless the form asks for an image.
Mixing formats in one submission. If a form takes one file per field, give it one tidy PDF per document, not a JPG for page one and a PDF for page two.
Questions people ask
Is a PDF better quality than a JPG?
Not by itself. A PDF made from a photo contains that photo. A PDF made by software from real text is sharper than any picture of the same page, because the text is stored as text.
Which is smaller, PDF or JPG?
It depends on the content. A typed page is far smaller as a text PDF than as a JPG. A photo is about the same size either way.
Can I turn a JPG into a PDF on my phone?
Yes. Open Image to PDF in your phone's browser, choose the photo from your gallery or take one, and download the PDF.
Do portals accept PNG or HEIC?
Some accept PNG. HEIC, the default photo format on many iPhones, is rarely listed. Check the form, and convert to JPG or PDF if it isn't mentioned.
Should I send my Aadhaar as a PDF or a photo?
Follow what the recipient asks for. If they have no preference, a PDF sent as a document stays legible and keeps both sides together.