Blog: simple guides to photos, PDFs and file sizes
A form rejects your photo. A portal wants one PDF. A file is "too big" and you do not know why. These short guides explain what is going on, in plain English, and show the quickest way out. Every example is worked out step by step, so you can check it yourself.
All articles
- 📉Internet slower than your contract? Here is how to prove itTest the right way, keep a log, use the official proof and write to your provider.9 November 2026
- 📶Is it your WiFi or your internet? A 5-minute checkTwo quick tests show if WiFi or the line is slow, plus easy fixes that cost nothing.9 November 2026
- 📱HEIC photo won't upload? How to turn it into a JPGForm says “file type not supported”? Turn iPhone HEIC photos into JPG in seconds, and stop it happening again.7 November 2026
- 🗜️How to Reduce Photo Size to 20, 50, 100 or 200 KB FreeThe quick way to get a photo under a KB limit for exam, job and government forms – without a blurry result.7 November 2026
- 📸How to Take a Passport Photo at Home With Your PhoneLight, wall, distance and size: how to get an accepted passport or visa photo with just your phone.7 November 2026
- 📕PDF Too Large to Email or Upload? 6 Ways to Make It SmallerToo big for email or a portal? Six fixes, from the fastest to the cleverest.7 November 2026
- 🚫Photo Rejected by an Online Form? 9 Reasons and FixesFile too big, wrong format, wrong pixels or shadows – find your error and fix it in minutes.7 November 2026
- 📄How to Scan Documents With Your Phone (Clear and Small)Light, angle and the right file type: phone scans that offices accept the first time.7 November 2026
- 🎯Photo under 20 KB or 50 KB? 9 questions, answered simplyPhoto 20–50 KB, signature under 20 KB: pixel sizes, JPG, minimum KB and phone tips in nine short answers.3 November 2026
- 📐What is aspect ratio, and how do you calculate it?16:9, 4:3, 3:2 explained simply: find the ratio of any photo, work out a missing width or height, and crop without surprises.17 October 2026
- 🔥How to calculate what your heating really costs per dayWatts to kWh, meter readings and unit prices: three easy ways to see what heating costs you each day this winter.17 October 2026
- 🗜️Why is my PDF so big? 9 common questions, answered simplyBig scans, merged files, email limits and lost text: nine common PDF size questions with short, honest answers.17 October 2026
- 🕒Clocks go back on 25 October 2026: how to work out your new time differenceEurope changes on 25 October, the US on 1 November. How to work out the new time gap to India, the US, Dubai and Sydney.12 October 2026
- 🖼️JPG vs PNG vs WebP: 9 common questions, answered simplyWhich format for photos, which keeps a transparent background, and does converting a JPG to PNG help? Nine short answers.12 October 2026
- 🔢How to convert KB to MB — and work out how big a file really isDivide by 1,000 — or 1,024? Why Windows and Mac show different sizes, and how to work out a photo's size before you upload it.12 October 2026
- 🖼️10x15 cm in pixels: the exact size for printing a 10x15 photo10x15 cm is 1181 x 1772 pixels at 300 DPI. A table for every DPI and a quick check if your photo is big enough to print.7 October 2026
- 📐One photo, many sizes: passport, school, office and online formsHow to get every size you need from one good photo — mm, pixels and DPI explained without the headache.6 September 2026
- 🧰Ten everyday file problems, and the quickest way out of eachA form will not take your photo, a portal wants one PDF, a scan came out sideways — ten common problems and the shortest fix.5 September 2026
- 📦File too big to upload? A step-by-step guideWhat to do when a website rejects your photo or PDF because it is too big.31 August 2026
- 📸Why a form says your photo is too big — and how to fix itKB limit or pixel limit? Find out which one your form means, and fix it in the right order.30 August 2026
- 📚How to send several documents as one PDFMost portals accept one file only. The right order: photos to PDF, then merge, then shrink.30 August 2026
What you will find here
- Photo sizes for forms: passport photos, pixels, millimetres and DPI, and why a website says your picture is too big.
- PDF help: how to put several documents into one PDF, make it smaller, and send it the way an office expects.
- File sizes: KB, MB and why your phone and your laptop show different numbers for the same file.
- Everyday questions: image formats, clock changes and other small things that cost time when you get them wrong.
Why we write these guides
Most file problems are not hard. They are just badly explained. An upload form says "max 200 KB" but not what to do. A passport office wants "35 x 45 mm" but the website asks for pixels. We write the explanation we wished we had found, and we link the free tool that fixes the problem.
All our tools run in your browser. Your photos and documents are not uploaded to our server, so they stay on your device.
Looking for a tool instead?
Go straight to all free tools, or try the tool finder and type what you need, for example "photo too big" or "merge PDF".