Guides
Measured answers, not rules of thumb
7 guides on what travels inside a photo, picking formats, shrinking files, and converting PDFs
Published · Updated
Most articles about image formats repeat the same approximate ratios without saying where they came from. The figures here were produced by a script in this project that encodes deterministic test images through the Canvas toBlob API in Chromium 151.0.7922.34 — the same code path the Image Converter runs in your browser. So when a guide says a photo lands at 62 KB, that is what this site would actually hand you. The source images are published for download so you can reproduce any of it.
What your files reveal
The information that travels inside photos and PDFs, and what it takes to remove it — tested rather than assumed.
EXIF data and privacy
We built a photo carrying GPS coordinates, camera model and a timestamp, converted it, and read the metadata back field by field. Includes what stripping EXIF does not protect you from.
What we found: Every field was gone after conversion — 245 bytes of metadata that a viewer never sees but any EXIF reader can pull out.
What a PDF reveals about who made it
A PDF tagged with an author, a draft title, keywords, an XMP packet and a reviewer's comment, run through merge, extract, split and PDF-to-image, then read back.
What we found: The author, title and XMP were dropped every time — but the reviewer's comment survived all three page tools, and text under a drawn black box was still extractable.
Choosing a format and a size
The two decisions that change your file more than anything else, with the numbers behind each.
JPG vs PNG vs WebP
Three test images encoded at four quality levels each, with every byte count published. Covers transparency, compatibility, and when each format is the wrong choice.
What we found: WebP is not always smaller. On dense texture at quality 0.4, JPG produced 149 KB against WebP's 184 KB.
How to reduce image file size
Format, dimensions, quality and metadata measured against each other on one source photo, so you can see which lever is worth pulling first.
What we found: Downscaling beats the usual rule of thumb: halving both sides left a quarter of the pixels but under a fifth of the bytes — 941 KB down to 5 KB once format and size are both handled.
Working with PDFs
What actually comes out when a document becomes images.
Reference
For when something goes wrong, or a word needs pinning down.
Troubleshooting conversion problems
Why a file gets rejected, why a job stalls, why a download vanishes — each with the cause rather than just the fix, plus the real size and format ceilings for all three tools.
What we found: Most failures trace back to one fact: the work happens on your own device, so the limits are your memory, not our servers.
Image and PDF terminology
Resolution, DPI, lossy and lossless, alpha, chroma subsampling, vector versus raster — defined plainly, each with a note on what it changes in practice.
What we found: Grouped by topic so you can read a section rather than hunt an alphabetical list.
Where to start
If you are about to share a photo, start with EXIF data and privacy and check the file in the EXIF Viewer. If you are here because a file is too big, read how to reduce image file size first — it ranks the four things you can change by how much they actually move the number. If you are choosing between formats, start with the format comparison. If something is failing outright, go straight to troubleshooting.
Prefer to just use the tools? The Image Converter, PDF Converter and Image Editor all run entirely in your browser, and the how-to page walks through each one.