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Ihtisham Khalil

Web developer and creator of ConvertPicto

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About Ihtisham Khalil

Ihtisham Khalil is an independent web developer. He designs, builds and maintains ConvertPicto, a set of free image tools that run entirely in the browser. It started as a small converter built for his own use, after getting tired of image tools that uploaded files to a server, added a watermark, or hid the download behind a sign-up.

ConvertPicto is open source under the MIT licence, so the code behind every claim on this site can be read and checked on GitHub. He has also written up how the PNG compressor works on DEV Community and in the article How I wrote a PNG compressor in plain JavaScript.

What he writes about

The articles on this blog cover image formats (PNG, JPG, WebP and AVIF), compressing images and getting them under a size limit, resizing, combining images into PDFs, favicons, and how online image converters handle your files. Where an article gives numbers, they come from tests described in the article itself.

How the numbers in the articles are produced

Benchmarks are run on the real ConvertPicto pages in headless Chromium. Output files are then opened with independent tools, such as Pillow for image decoding, scikit-image for quality scores (SSIM and PSNR) and a PDF library for page counts, so the tool is not marking its own homework. Each article says what was tested, on which images, and what the limits of the test are.

Get in touch

Corrections, bug reports and requests are welcome at contact@ihtishamkhalil.com or through the contact page.

Articles by Ihtisham Khalil

How to compress an image to 20, 50 or 100 KB (and what you lose)
Tested on real photos: what a 20, 50, 100, 200 or 500 KB limit does to quality and dimensions, and how to avoid a blurry result.
24 October 2026 · 5 min read
We checked all 28 image conversions pixel by pixel
28 conversions, each run in headless Chromium and compared against an independent decoder. What is identical, what is lossy, and why.
23 October 2026 · 4 min read
How big will your image PDF be? We measured it
Page size does not change the file size, but quality does, a lot. Measured PDF sizes from JPG and PNG sources.
23 October 2026 · 4 min read
JPG vs WebP quality settings: what each level really costs in file size
Nine quality settings, two formats, five photos, measured. Where the file-size curve is gentle, and where it falls off a cliff.
23 October 2026 · 4 min read
PNG vs JPG vs WebP: what we measured on photos, screenshots, text and charts
There is no best format, only a best format for each kind of image. Measured sizes and quality scores for photos, screenshots, text and charts.
23 October 2026 · 4 min read
Resize or compress first? Measuring what actually shrinks an image
Image size scales with pixel count, so resizing beats lowering quality. Here are the measured numbers, and the order that works best.
23 October 2026 · 4 min read
Writing a real PNG compressor in vanilla JavaScript (no WASM, no libraries)
Median-cut quantization, Floyd–Steinberg dithering, hand-built PNG chunks, and the four browser traps that cost me an evening each.
07 October 2026 · 6 min read
Are online image converters safe? What actually happens to your files
Most converters upload your file to a server you know nothing about. Here's how to tell which ones do, and when it actually matters.
09 September 2026 · 6 min read
JPG vs PNG vs WebP vs AVIF: which image format should you use?
Five formats, one decision. Here's what each one is actually good at, with a rule of thumb you can apply in ten seconds.
09 September 2026 · 6 min read
How to combine multiple images into one PDF
Every method, on every device — plus the page-size and quality settings that decide whether your PDF is 200 KB or 20 MB.
09 September 2026 · 5 min read
How to make a favicon: every size and format you actually need
Which sizes you actually need, the exact HTML to paste, and the three reasons a favicon usually fails to appear.
09 September 2026 · 5 min read
How to reduce image file size without losing quality
Do these three things in the right order and a 4 MB photo becomes 80 KB with no visible difference. The order matters more than the tools.
09 September 2026 · 6 min read
What is a WebP file, and how do you open one?
Why the internet keeps giving you files you can't open, how to open them anyway, and when WebP is actually the right choice.
09 September 2026 · 5 min read