JPG vs PNG vs PDF: Which Format Should You Use (and When)

JPG, PNG, PDF — we use them every day without thinking about which is right. Pick the wrong one and you get a blurry logo, a huge email attachment or a document that won’t open properly. Here’s the plain-English guide to what each format is for, and how to switch between them when you need to.

The 10-second answer

• JPG (or JPEG) → photos. Small files, millions of colours, slight quality loss you won’t notice on a photograph.
• PNG → screenshots, logos, diagrams. Perfectly sharp, supports transparency, but bigger files.
• PDF → documents. Multiple pages, fixed layout, selectable text, looks the same everywhere.

If you remember nothing else: photos = JPG, graphics with text = PNG, anything meant to be read as a document = PDF.

JPG — built for photographs

JPG uses lossy compression: it throws away detail your eye won’t miss to make files small. That’s perfect for photos, where smooth colour gradients hide the loss. It’s the right choice for camera pictures, and it’s why a 12-megapixel photo is only a couple of megabytes.

Its weaknesses: it can’t do transparency, and it’s bad at sharp edges — text and thin lines get fuzzy “artefacts”. So never save a screenshot or a logo as JPG.

PNG — built for sharp graphics

PNG is lossless: it keeps every pixel exactly. That makes it ideal for screenshots, logos, icons, diagrams and anything with text or hard edges. It also supports transparency, so a logo can sit on any background.

The trade-off is size: a detailed photo saved as PNG can be several times bigger than the JPG version. So use PNG for graphics, not for photographs.

PDF — built for documents

A PDF isn’t really an image format at all — it’s a document container. One PDF can hold many pages, mix text and images, keep its exact layout on any phone, computer or printer, and store real selectable, searchable text. That’s why contracts, CVs, invoices, manuals and forms are PDFs.

If you have several images that together form a document — receipts, a multi-page scan, a portfolio — they belong in a PDF, not as a pile of loose JPGs.

Converting between them (free, in your browser)

You’ll often need to switch formats. Here’s which tool does what:

• Images into a document: JPG to PDF or PNG to PDF — bundle photos or screenshots into one tidy PDF, one image per page.
• A PDF page back into an image: PDF to JPG for photo-style pages, or PDF to PNG when text must stay razor-sharp (for slides, websites, docs).

A quick rule for the reverse direction too: exporting a page to PNG if it has text you want crisp, to JPG if it’s mostly photographic and you want a smaller file.

A note on quality and privacy

When you convert image-to-PDF here, JPGs are embedded with no extra compression, so you don’t lose quality twice. And like every PDFAgent tool, conversions run entirely in your browser — your photos and documents are never uploaded, which is exactly what you want for anything personal.

Pick the format for the job — photo, graphic or document — and convert freely when you need the other one.