Skip to main content
When no output format is specified, Openinary automatically selects the smallest format the requesting browser supports.

​
How it works

1

Detect browser support

Reads the Accept header and User-Agent to determine which modern formats are supported.
2

Analyze content

Evaluates whether the image is a photo, graphic, or contains transparency to pick the best codec.
3

Pick the smallest result

Encodes in candidate formats, compares sizes, and serves the winner.Priority: AVIF → WebP → JPEG / PNG

​
Typical size reductions

Original format→ AVIF→ WebP
JPEG40–50% smaller25–35% smaller
PNG50–70% smaller25–40% smaller
Actual savings depend on image content and original compression level.

​
Manual format override

Use the f parameter to force a specific format regardless of browser support. 
GET /t/f_avif,q_80/image.jpg
GET /t/f_webp,q_85/image.jpg
GET /t/f_jpeg,q_90/image.jpg

​
Next steps

Image Transformations

Full reference for resize, crop, rotate, and format parameters.

Upload & Cache Warming

Pre-generate optimized variants at upload time.