You have the right picture in the wrong format: a transparent logo saved as a JPG, a screenshot a form refuses because it wants JPG not PNG, or a folder of heavy images you want to slim down to WebP for a website. Converting is quick once you know which direction to go and the one trap that catches people out. This guide is the practical “how and when” — not the deep theory — and every conversion happens in your browser, so your images never leave your device.
When to convert each direction
There is no single “best” format, only the right one for where the image is going. A few rules cover almost everything:
- Convert to JPG when you need a photo that opens absolutely everywhere — every device, app, and ancient piece of software handles it. It is also the safe choice for emailing photos or uploading to a form that specifies it.
- Convert to PNG when you need a transparent background or pixel-perfect edges — logos, icons, diagrams, screenshots — or a lossless working copy to edit without it degrading each time you save.
- Convert to WebP or AVIF when the image is bound for a website and you want it smaller. These modern formats store the same picture in fewer bytes at the same visible quality, so pages load faster.
If you want the full reasoning behind each format — quality, transparency, and browser support compared side by side — see our PNG vs JPG vs WebP vs AVIF guide. Here we will stick to making the change.
The transparency gotcha (PNG to JPG)
This is the one conversion that surprises people, so it deserves its own warning. JPG cannot store transparency. When you convert a PNG that has see-through areas — a logo with no background, say — into a JPG, those transparent pixels have to become something, and the converter fills them with a solid colour, usually white.
The result: a logo that looked clean on any page suddenly arrives sitting in a white box. It is not a bug; it is the format doing what it must. So before converting PNG to JPG, ask whether the image relies on transparency. If it does, stay on PNG (or use WebP, which keeps transparency and shrinks the file). If transparency genuinely does not matter — a photograph saved as PNG, for instance — converting to JPG is the right call and cuts the size dramatically with no visible loss.
Converting to WebP or AVIF to shrink web images
For anything destined for a website, converting JPG or PNG to WebP (or AVIF) is one of the easiest performance wins available. A photo re-encoded as WebP is typically noticeably smaller than the JPG it came from at the same visible quality, and every current browser displays it. Because WebP supports transparency too, it can also replace a bulky transparent PNG without the white-box problem above.
The practical rule: if the image lives on a modern web page, convert it to WebP for the faster load. Keep a JPG or PNG copy only if it also needs to be downloaded, emailed, or opened in older software.
Converting back to JPG or PNG for compatibility
Conversion goes both ways. If someone sends you a WebP or AVIF file your photo editor, a print service, or an older app will not open, convert it back to JPG (for photos) or PNG (for graphics and transparency). The same applies when a form or template insists on one specific type — match what it asks for rather than fighting it.
How to convert an image step by step
Here is the workflow using a browser-based image converter:
- Open the tool and drag in your image — or a whole batch of them — straight from your folder. The files are read on your device; nothing is uploaded.
- Pick the output format — JPG, PNG, WebP, or AVIF — based on where the image is heading.
- Mind transparency. If you are going to JPG from a transparent PNG, remember the see-through areas will be filled with a background colour.
- Convert, then preview to confirm the result looks right.
- Download the converted image, or the whole batch at once.
Because the image converter runs entirely in your browser, the conversion happens locally and the result is handed straight back to you — safe for private photos, client files, or anything you would rather not upload.
Batch converting a whole folder
Converting images one by one is fine for a single file and tedious for fifty. Drop the entire folder into the converter, choose one target format, and every image is re-encoded in a single pass — ideal for turning a directory of PNG screenshots into lighter JPGs, or product photos into WebP for a shop. One tip: batch by type, since the transparency rule applies to the whole set. Separate any transparent images so you do not accidentally flatten a logo into a white square.
Convert first, then shrink further
Converting to a leaner format already reduces size, but you can go further. After converting photos to JPG or WebP, run them through the image compressor to trim the byte count even more without changing the dimensions. And if your source files are iPhone photos in the HEIC format — which most apps and forms still cannot open — a dedicated HEIC to JPG converter handles that special case in one step. Convert to the right format, compress if needed, and it all stays private in your browser.
Frequently asked questions
How do I convert a PNG to JPG? Open a browser-based converter, add the PNG, choose JPG as the output, and download the result. Remember that JPG has no transparency — any see-through areas in the PNG will be filled with a solid background colour, so only convert when transparency does not matter.
Should I convert my images to WebP? For images on a modern website, yes — WebP files are smaller than JPG or PNG at the same visible quality and every current browser supports them. Keep a JPG or PNG copy only if the image also needs to open in older software or be emailed widely.
Can I convert several images at once? Yes. A batch converter lets you drop in a whole folder and re-encode every image to one chosen format in a single pass. Group files by type so the transparency rule applies cleanly to the whole batch.