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Why is my PDF to JPG file so large? (and how to fix it)

By DeckleUpdated

A JPG exported from a PDF is usually too large because the resolution is higher than the job needs. Export again in PDF to JPG with Resolution one step lower, such as Standard instead of Print, and set JPEG quality to Balanced or Smaller. Lowering the resolution cuts the file far more than lowering the quality.

PDF to JPG

Same physical page, more pixels

150 DPI

Letter: 1,275 × 1,650 pixels

300 DPI

Letter: 2,550 × 3,300 pixels

Double each dimension → four times the pixels

Example calculation · nominal sizes for an 8.5 × 11-inch page. Actual exports depend on page geometry and rounding.

How to make a PDF to JPG file smaller

  1. Note the size of the JPG you have and the limit you need to meet, such as 1 MB for an upload form.
  2. Open PDF to JPG and choose the PDF again, or drop it onto the page.
  3. Under Resolution, choose one step lower: Standard (150 DPI) instead of Print, or Screen (72 DPI) instead of Standard.
  4. Under JPEG quality, choose Balanced, or Smaller if you still need to save space.
  5. If only some pages are needed, choose Choose pages and type them.
  6. Choose Export images and check the new file size in your downloads folder.

Change one setting at a time. If the file is now small enough, you know which change did it and the image stays as sharp as possible.

Resolution or quality: which to change first

Resolution sets the number of pixels. Quality sets how much detail each part of the image keeps when it is compressed. Halving the DPI quarters the pixels, so it has the bigger effect on size.

Change Effect on pixels Effect on file size Effect on looks
Print → Standard a quarter as many much smaller fine on screens; less room to zoom
Standard → Screen a quarter as many much smaller small text hard to read
Maximum → Balanced same noticeably smaller almost no visible change
Balanced → Smaller same smaller small text and sharp edges soften

Maximum saves at 100% quality, Balanced at 92% and Smaller at 75%. The jump from Maximum to Balanced often saves a lot for little visible loss, which is why Balanced is the default.

Example: a scanned A4 letter exported at Print and Maximum gives a 2480 × 3508 image several megabytes in size. At Standard and Balanced it is 1240 × 1754 and a fraction of that, and the text is still easy to read on screen.

Why some pages make bigger files than others

File size depends on what is on the page, not just the settings. A page of black text on white has large plain areas that compress well. A page with a full-bleed photo, a shaded background or a coloured scan has detail everywhere and produces a much larger JPG at the same settings. In one export, the photo cover of a brochure can be several times the size of a text page.

If a text-heavy page is the problem, try PDF to PNG as well: flat text pages can be compact as PNG and stay crisper. PDF to PNG or JPG explains when each wins.

Upload limits by size

Deckle does not have a target-size option. To hit a limit, export at a setting, check the size, and step down if needed. For a typical A4 page, Standard with Balanced is a sensible first try for forms that accept up to a few megabytes; converting a PDF to JPG for an online form walks through it.

Tips

  • Lower resolution before quality. It saves more space and keeps edges cleaner.
  • Do not go below Standard for text people must read. At Screen, body text gets hard to read.
  • Export only the pages you need. Fewer images means a smaller ZIP.
  • Check after download. The real file size is in your downloads folder; it varies with page content.

Frequently asked questions

Why is my JPG bigger than the PDF?

A PDF stores text as compact shapes. A JPG stores every pixel of the page, so a text page can be larger as an image than as a PDF.

Can I set an exact file size?

No. Choose a lower Resolution or JPEG quality, export, and check the size.

What setting gives the smallest JPG?

Screen with Smaller. Body text may be hard to read at that size.

Does lowering the quality change the pixel size?

No. Only Resolution changes the pixel size. Quality changes compression.

Related tools

Sources