JFDI Blog

Tag: file size

  • How to compress a PDF to send by email

    To compress a PDF for email, shrink the pictures inside it: that’s where almost all the size is. Open it in the JFDI PDF toolkit, go to the Finish tab, choose Balanced (or Smallest for a tight limit) under Making the file smaller, and download. The new size is shown next to the old one. It’s free, there’s no upload, and there’s no file-size cap.

    Compress a PDF

    How big can an email attachment be?

    Email serviceLimitSource
    Gmail (personal)25 MB; anything bigger is sent as a Google Drive linkGoogle
    Outlook with an internet account such as Outlook.com20 MBMicrosoft
    Outlook with a work (Exchange) account10 MB by default; your IT team may have changed itMicrosoft

    Outlook’s limit covers the whole email, and the way attachments are encoded for sending can add up to a third to their size on some systems, so aim well under the limit. For a 10 MB limit, aim for 7 MB.

    Step by step

    1. Open the PDF toolkit and drop in your PDF, or choose Compress on the start page.
    2. Go to the Finish tab and find Making the file smaller.
    3. Choose a setting (see the table below). Start with Balanced.
    4. Download PDF. The message shows the new size beside the old one. If it’s still too big, try Small or Smallest.
    SettingPictures becomeGood for
    Keep as they areUnchangedText documents, or when quality matters most
    BalancedUp to 2,200 pixels, good-quality JPEGMost files: noticeably smaller, no visible loss on screen
    SmallUp to 1,500 pixelsSharing and reading on screen
    SmallestUp to 1,000 pixels, lower qualityEmail with a strict size limit

    Pictures are only replaced when the result is actually smaller. Unused data, including pages you deleted, is always removed.

    Why some PDFs barely shrink

    Compression works on pictures. A PDF that’s mostly text, such as a report exported from Word, is already compact: a page of text takes a few kilobytes, so there’s little to remove. If such a file is large, it’s usually because of:

    • Embedded fonts, especially several large ones. These can’t be removed without changing how the text looks.
    • Vector drawings such as detailed maps, plans or charts with thousands of points. For these, Turn every page into a picture (150 dpi) can help, but the text then can’t be selected, searched or read by screen readers.
    • Lots of pages. Split the document instead: the Finish tab can split a PDF into several files by page ranges.

    Scanned documents are the opposite: every page is a full-size photo, so they often shrink by most of their size.

    Other ways to get under the limit

    • Remove pages nobody needs, such as blank pages from a scanner, in the Pages tab.
    • Split the file into two emails with Splitting into several PDFs.
    • Scan at a lower resolution next time: 150 to 200 dpi is plenty for reading on screen.
    • Use a link instead of an attachment for very large files.

    Is it safe?

    The PDF is compressed inside your browser and never uploaded, so a payslip or a contract doesn’t pass through anyone’s server. If it’s confidential, add a password in the same Finish tab (AES-256 encryption) and send the password by a different route.

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  • How to compress an image to exactly 100 KB (or any size)

    To compress an image to a specific size such as 100 KB, use a tool that aims for a file size rather than a quality setting. In the JFDI image editor, open the picture, choose Aim for a size under Save as, type 100 KB, and download. The editor tries quality levels until it finds the best one that fits under 100 KB. If even the lowest sensible quality is too big, it makes the picture smaller in pixels until it fits, and tells you.

    Compress an image to a size

    Why forms ask for 100 KB

    Job applications, exam registrations, government portals and membership systems often set a maximum file size for photos and signatures, commonly somewhere between 20 KB and 500 KB. A photo straight from a phone is usually 2 to 5 MB, so it needs to be 20 to 50 times smaller.

    You can get there by trial and error with a quality slider, or let the tool do the search.

    Step by step

    1. Open the image editor and drop in your picture (or several; each one is handled separately).
    2. Crop it first if the form wants a particular shape, such as a square or passport proportions. Click the crop button above the picture, or pick a shape under Crop.
    3. Resize it if the form gives pixel dimensions, under Resize. A smaller picture needs less compression to hit a size, so it looks better. For a 100 KB limit, around 800 to 1,200 pixels on the longest side is usually plenty.
    4. Under Save as, choose JPG and switch to Aim for a size. Type 100 KB (or whatever the form says).
    5. Check the preview. The list on the left shows the new file size. Zoom to 100% to check faces and text are still clear.
    6. Download.

    The editor saves each file as close to the target as it can without going over, so it won’t fail a strict upload check.

    KB or KiB?

    Some forms count 1 KB as 1,000 bytes and others as 1,024. If a form rejects a file that should fit, aim a few kilobytes lower, such as 95 KB for a 100 KB limit.

    Which format?

    FormatUse it when
    JPGPhotos and scans for forms. Accepted everywhere.
    PNGSignatures, logos and screenshots with sharp edges and few colours.
    WebPWebsites. Smaller than JPG at the same quality, but some forms won’t accept it.

    For a PNG, quality can’t be lowered because PNG is lossless. The editor reduces the number of colours instead (256 colours usually looks identical for screenshots and logos), then the pixel size, until the file fits.

    Getting the best quality at a small size

    • Crop away background. Fewer pixels of wall means more detail for the face.
    • Resize before compressing. A 1,000-pixel photo at good quality looks better than a 4,000-pixel photo squeezed hard.
    • Avoid noise. Photos taken in dim light have grain, which compresses badly. Take the photo in good light.
    • Check text at 100% zoom. For scanned documents, make sure small print is still readable.

    What happens to the photo’s hidden details

    Phone photos contain the location where they were taken, the date and the camera model. The editor removes these by default, which also saves a few kilobytes. See how to remove location data from photos.

    Is it private?

    Yes. The photo is compressed in your browser and never uploaded. That matters for ID photos and signatures, which are exactly the images you shouldn’t scatter across free websites.

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