File Formats

Tech 05 Sep 2026 8 min read

How File Thumbnails Work and Why Previews Sometimes Disappear

Open a folder of photos and you may see dozens of miniature images before opening a single file. A video may show a frame from the recording, while a document may display a tiny version of its first page. These small images are thumbnails: previews created to help you recognise files quickly. A thumbnail is usually not the file itself. It is a smaller representation that the operating system, file manager, photo application, or another program creates from the original data. That distinction explains why previews can appear slowly, become outdated, or disappear even when the original files are still intact.

Files File Formats

Tech 03 Sep 2026 7 min read

What File Extensions Mean and Why They Matter

A photo might end in .jpg, a document in .pdf, and a compressed archive in .zip. These short endings are file extensions: parts of filenames that help people and software identify what kind of data a file is expected to contain. File extensions seem simple, but they explain several everyday puzzles. Why does double-clicking one file open a photo viewer while another opens a spreadsheet? Why can changing .jpg to .png make a file harder to open without actually converting the image? And why can a file sometimes open even when its extension is missing or wrong?

Files File Formats

Tech 03 Sep 2026 8 min read

JPEG vs PNG: Why the Same Image Can Have a Very Different File Size

Two image files can show almost the same picture yet occupy very different amounts of storage. A photograph saved as JPEG may be much smaller than a PNG version, while a screenshot with text and flat colours can behave quite differently. The reason is not simply that one format is newer or better. JPEG and PNG are designed to preserve image information in different ways. Understanding that difference makes it easier to choose a format for photos, screenshots, graphics, websites, and files you plan to edit again.

Images JPEG