PNG, JPG or WebP: which format to use on each network

The three output formats

SocialCutter generates the same image cropped to the catalogue dimensions and lets you choose which format it comes out in. There are three: PNG, JPG and WebP. The difference is not image quality as such, but how it is stored: whether it supports transparency, how much it weighs and how much information is discarded during compression.

Format	Transparency	Relative weight (photo)	Compression	Best for
PNG	Yes, alpha channel	High	Lossless	Logos, screenshots with fine text, designs with a transparent background
JPG	No	Low	Lossy (tunable)	Photographs and creatives with a filled background
WebP	Yes	Lowest of the three	Lossy or lossless	Web, CMS and whenever weight really matters

Transparency, weight and quality

Three questions settle almost every case.

Do I need transparency? If the design has a transparent background so it can sit on a colour or a photo, the answer is PNG. JPG has no alpha channel: whatever was transparent gets filled with a solid colour. WebP does support transparency, but if you are handing the file to a system that handles it poorly, PNG is the safe bet.

How much does it weigh? At the same dimensions, JPG and WebP weigh considerably less than PNG on images with many tones (photos, gradients). PNG wins on flat-colour images (logos, icons, UI screenshots), where there is barely any gradient to compress.

How much quality do I need? JPG and lossy WebP discard information as they compress. For photos, a quality between 80 and 90 is almost never distinguishable from the original and saves a lot of weight. PNG loses nothing, but takes up more.

How to pick the format in SocialCutter

The format is set in the request options object. Its three fields are format, quality and background_color:

curl -s -X POST "https://api.socialcutter.theboomer.dev/api/v1/images/process" \
  -H "X-API-Key: sc_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "source": { "type": "url", "value": "https://example.com/master.jpg" },
    "destinations": [
      { "platform": "instagram", "format": "post" },
      { "platform": "linkedin", "format": "post" }
    ],
    "options": { "format": "jpg", "quality": 88 }
  }' | jq

• format: png, jpg or webp. The default is webp.
• quality: an integer from 1 to 100. The default is 85. It affects the lossy formats (JPG and WebP); with PNG it does not change quality.
• background_color: padding for contain mode. The default is #000000.

Scope note: format is a request option, not a destination one. It applies to every output in that call. If you want PNG for one output and JPG for another, that is two requests, and each charges 1 use per destination. The same goes for quality.

Which format to recommend per destination

Destination	Recommended format	Why
Product photo or creative with a filled background	JPG or WebP	Less weight, same perceived quality
Design with a transparent background or a logo	PNG	Keeps the alpha channel with no doubt
UI screenshot or fine text	PNG	Avoids the JPG artefacts on sharp edges
Destination for your own site or CMS	WebP	The lightest and compatible with current browsers
When the network is strict about uploads	JPG	The most universal format for publishing
YouTube channel banner	JPG or PNG	Large size (2560x1440): control the weight with quality
Cover or thumbnail with fine text	PNG	Small text appreciates the absence of loss

WebP on social networks: read the fine print

WebP is the default because it is the lightest, and it is an excellent choice for your website, your CMS or your media library. But do not assume every social network accepts a WebP upload.

Each platform sets which formats it accepts, which it recommends and how it recompresses what it receives. That list changes over time, and we do not publish it here as if it were fixed: before automating a publish, check the network’s official help centre and, when in doubt, generate the output as JPG or PNG, the most universal upload formats. Our job is to give you the file in all three formats; which one each network accepts is up to the network.

One more honest detail: many networks recompress on publish, so an immaculate PNG can end up as JPG. When the goal is to publish rather than archive, JPG is the most predictable option.

We are not a generic converter

Worth clarifying, because the name misleads: SocialCutter is not a file format converter. You do not upload any file and download it in another format. What it does is take a raster image and generate the catalogue destinations (6 platforms, 13 destinations) at their exact dimensions; the output format is an option inside that process.

That means:

• It does not accept SVG, PDF or documents: the input is a raster image (JPG, PNG or WebP).
• It does not take arbitrary dimensions: you do not ask for “800x400”, you ask for a catalogue destination.
• It does not convert loose files without going through the crop to the destinations.
• It does not edit the image: no retouching, no compositing, no background removal.

To change format without touching dimensions there are conversion tools; to get every exact size the networks ask for, there is SocialCutter. The destinations and their pixels are in Social media image sizes: dimensions and ratios.

Cost

• 1 use per destination (platform and format) per request.
• The output format does not change the price.
• Duplicate destinations in one request are not charged twice.
• Failed processing jobs are refunded.
• Plans at 0, 3, 9 and 29 EUR, with the API and the MCP server included.

Typical errors

Error	What happens	What to do
Asking for PNG on a large photo	The file is heavy and may exceed 5 MB	Use JPG with quality 80-90, or WebP
Asking for JPG with transparency	The transparent background is filled with colour	Use PNG
Expecting a different format per destination	format is per request, not per destination	Split into two requests
Lowering quality with PNG	It does not change quality, only weight	For variable quality, use JPG or WebP
Uploading a file over 5 MB	The API returns 413	Compress beforehand or request a lighter output
Publishing WebP where the network only takes JPG	The platform rejects or recompresses the upload	Check the network help centre and generate JPG

Next steps

• Sizes and ratios: Social media image sizes: dimensions and ratios
• Automation: Automating social media images: 4 real paths
• Design source: Canva + SocialCutter: one design, every size
• Terminal: Process images with the API from the terminal (curl)
• Code: Process images with the SocialCutter API from Python
• API documentation: https://docs.socialcutter.theboomer.dev