Use a mix of formats, on purpose
PowerPoint, Google Slides and Keynote happily accept both PNG and JPG, and the best decks use each where it shines rather than picking one for everything. The rule of thumb: if the image has text, sharp lines or transparency, use PNG; if it is a photograph, use JPG to keep the file small. The table maps the usual slide ingredients.
| On the slide | Best format |
|---|---|
| Screenshot of an app or page | PNG |
| Chart, diagram or flowchart | PNG |
| Logo or cut-out graphic | PNG (transparent) |
| Photograph | JPG |
PNG for screenshots, diagrams and logos
Anything with fine text or hard edges belongs in PNG. A screenshot of an interface, a flowchart, a chart exported from a spreadsheet or a brand logo all depend on lossless pixels so the lettering stays legible when the slide is blown up on a wall. PNG also carries transparency, so a logo or an icon sits cleanly over any slide colour instead of arriving in a white rectangle. If you grabbed a screen capture, see saving a screenshot as PNG. And if you need to print the deck later, the choices overlap with our guide to the best format for print.
JPG for photos to keep the deck light
Photographs are the one case where PNG works against you. A full-resolution photo saved as PNG can be many megabytes, and a deck full of them quickly becomes too big to email. JPG compresses the same photo to a fraction of the size with no visible loss at slide scale, where the audience sits metres from the screen. So when a slide is dominated by a photograph, reach for JPG — you can convert PNG to JPG for any photo you already pasted in as PNG.
How to stop a deck from bloating
Oversized images are the number one cause of a presentation that will not attach to an email. Two habits fix it. First, do not paste 6000px photos straight off a camera or phone — they carry far more detail than a slide can show. Second, compress images before or after they go in: a quick pass through a PNG compressor can cut a screenshot-heavy deck by half without any visible change. Converting photo PNGs to JPG, as above, does the rest. The goal is a file light enough to share that still looks crisp on the projector.
Exporting slides and choosing DPI
Sometimes you want a whole slide as an image — for a thumbnail, a social post or a handout. PowerPoint, Google Slides and Keynote all export slides to PNG or JPG: choose PNG when the slide is mostly text and diagrams, JPG when it is mostly a photo. Match the resolution to the destination. For a projector or screen the slide only needs to look sharp at screen size, so a modest export is fine. For a printed handout, export at a higher DPI so text and lines stay clean on paper. Explore the full PNG toolkit to prepare any image before it goes on a slide.
Frequently asked questions
- PNG or JPG for slides?
- Use both. PNG for screenshots, diagrams, charts and logos where text and edges must stay sharp or you need transparency, and JPG for full photographs where it keeps the file far smaller. Mixing them keeps the deck crisp and light.
- Why is my PowerPoint file so huge?
- Almost always oversized PNG photos. A full-resolution photo pasted as PNG can be many megabytes each, and a handful of them bloats the deck. Convert those photos to JPG, or compress the images, and the file shrinks dramatically.
- Can I export a whole slide as an image?
- Yes. PowerPoint, Google Slides and Keynote can all save slides as PNG or JPG. Export as PNG when the slide is mostly text and diagrams so it stays sharp, and as JPG when it is dominated by a photograph.
- What resolution do images need for a projector?
- A projector or screen is low resolution, so images only need to look good at the slide pixel size — there is no benefit to embedding a 6000px photo. Printed handouts are different: those want higher DPI so detail survives on paper.
- Do I need transparent PNGs in a deck?
- Often, yes. A logo or icon with a transparent background sits cleanly over any slide colour, where a JPG would arrive in an ugly white box. That transparency is a key reason to keep logos and cut-out graphics as PNG.