Quick answer: For social media posts, use PNG for screenshots, interface images, text cards, and launch graphics; use JPG for photographs. WebP is a valid modern option that compresses both kinds well, but support and caching vary.

That's the whole rule. The reason is how the two formats compress.

What each format does

JPG compresses by discarding detail in smooth areas. It's excellent at shrinking photos, where human eyes don't notice subtle color changes. It is terrible at sharp edges: text, lines, logos, and UI borders get compression artifacts, look fuzzy, or smear.

PNG is lossless. It preserves every pixel, which keeps text crisp and lines clean. It is larger for photos, but for text-heavy graphics it's often smaller than an equivalent JPG and dramatically better looking.

The decision table

Image content Format Why
Product screenshot / UI PNG Sharp text and borders
Text card, quote, comparison PNG No fuzz around letters
Logo on a flat background PNG Clean edges, transparency
Launch hero card PNG Text must stay readable
Phone / person / landscape photo JPG Smaller, looks fine
Photo with an overlay headline PNG Protect the headline
Animated graphic GIF or MP4 Platforms generally prefer MP4
Universal web export WebP Smaller, but verify support

File size limits

Platforms cap uploads:

  • X: 5 MB per image.
  • Instagram: around 30 MB for images, but compression happens regardless.
  • LinkedIn: generous, around 10 MB.
  • Facebook: around 8 MB for photos.

A 1080 × 1350 text card exported as PNG is usually well under 2 MB, so the limit rarely binds. If a PNG does get big, it's usually because of a photographic background; either use JPG for that case or simplify the background.

Why JPG screenshots look bad

The screenshot problem shows up in every launch timeline. A JPG of a dashboard creates little shimmering artifacts around text, blurs the grid lines, and smears the icons. At a small size in the feed, that reads as "low quality product."

The same screenshot exported as PNG at 2x stays crisp after upload.

What about WebP?

WebP is smaller for both photos and graphics, and modern browsers and major platforms accept it. If your workflow reliably exports WebP, it's a good default for web and social link cards. In practice, PNG remains the safest, most predictable choice for social posts because some clients and older scrapers cache or mis-handle WebP.

Export settings that actually matter

  • Export at 2x for anything with text, then downscale to the target size.
  • Export at the exact target ratio (e.g., 1200 × 675 for X) rather than resizing after export.
  • Use sRGB color so the colors don't shift on the web.
  • For JPG photos, quality 80–85 is a good balance.

Frequently asked questions

Is PNG better than JPG for social media? For text and screenshots, yes. For photos, JPG is smaller and looks fine.

Why is my PNG huge? Flat-color PNGs are tiny; PNGs of photos are large. If the image is a photograph, use JPG. If it's a designed card with a photo background, flatten the background to JPG quality and keep the overlay text as sharp elements.

Can platforms convert my image anyway? They recompress on upload, but they can't recover detail lost to a bad JPG. Start crisp.

Does the format matter for OG images? PNG and JPG both work for 1200 × 630 OG cards; keep the file under 1–2 MB so the scraper loads it quickly.

What about screenshots with rounded corners? Keep them PNG; rounded corners usually imply transparency, which JPG doesn't support.

For the next launch card you make, save it as PNG before anything else. If it's a photograph, switch to JPG.