Is This the Wrong Image Format for the Job?

A format is wrong only relative to a requirement. Diagnose the failed property before replacing it.

Symptom map

Symptom	Possible mismatch
Photographic PNG is huge	Lossless format used for delivery photo
Transparent background vanished	Opaque destination such as JPEG
Logo becomes soft when enlarged	Fixed raster derivative used instead of vector master
Receiver cannot open file	Compatibility mismatch
Animation disappears	Still-image workflow
Print result lacks required fidelity	Delivery copy substituted for production master

Confirm before converting

Write the missing requirement.
Check whether the source actually contains it.
Determine whether another format can represent it.
Verify the receiving application supports that implementation.
Keep the master and test one derivative.

Do not use conversion as repair

JPG to PNG cannot recover lost detail or create alpha. PNG to WebP can be useful for compatible web delivery but does not fix poor dimensions. If the fault is corruption, resizing, color policy, or platform re-encoding, changing format alone is incomplete.

Requirement-by-requirement fixes

Compatibility

Create a derivative accepted by the receiver while preserving the original. Do not assume browser support equals editor or messaging-app support.

File size

Check dimensions and content before changing format. A photographic PNG may benefit from a photo-oriented encoding; a tiny flat graphic may not.

Transparency

Use an alpha-capable output and inspect edges. If an opaque destination is mandatory, choose the matte intentionally.

Editability

A raster delivery file cannot replace a layered or vector master. Recover the original project rather than attempting repeated conversions.

Professional recommendation

Write a one-sentence requirement—“must display in this app with transparency under 500 KB”—and reject every candidate that fails any mandatory clause. This prevents optimizing one visible symptom while breaking another property.