Compression & Export
Image compression, format conversion, and responsive variant generation.
Overview
Picture Optimizer's export pipeline compresses images, converts formats, optionally creates responsive variants, and writes EXIF metadata — all in a single operation.
Output Formats
| Format | Best For | Notes |
|---|---|---|
| WebP | General web use | Excellent compression, wide browser support |
| AVIF | Maximum compression | Smallest files, growing browser support |
| JPEG | Photography, gradients | Universal compatibility |
| PNG | Graphics, transparency | Lossless option available |
| Original | Keep current format | Applies compression without converting |
Quality Presets
Instead of raw quality numbers, Picture Optimizer uses named presets that map to optimized quality values per format:
| Preset | JPEG | WebP | AVIF | PNG | Use Case |
|---|---|---|---|---|---|
| Maximum | 98 | 98 | 80 | Lossless | Print, archival |
| Very High | 90 | 90 | 65 | Lossless | Photography |
| High (Sharp) | 82 | 82 | 55 | Lossless | Logos, sharp detail |
| Medium (Smooth) | 75 | 75 | 45 | Palette | Photos, gradients |
| Low | 60 | 60 | 35 | Palette | Thumbnails |
| Minimum | 35 | 35 | 20 | Palette | Tiny file size |
Quality values are fetched from the API as a single source of truth. The plugin displays estimated output sizes based on these values before you commit.
Responsive Variants
When enabled, Picture Optimizer generates multiple sizes of each image for responsive srcset delivery:
- Configure breakpoints (e.g., 480px, 768px, 1024px, 1440px)
- Each variant is compressed with the same quality preset
- WordPress receives the full-size image; variants are stored alongside it
EXIF Metadata Writing
During export, AI-generated metadata is embedded directly into image file headers:
- EXIF — Title, description, keywords
- XMP — Extended metadata fields
- IPTC — Caption, copyright, keywords
This means the metadata travels with the file if it's downloaded or syndicated.
Size Estimation
Before exporting, the plugin shows estimated output sizes based on:
- The original image dimensions and file size
- The chosen format and quality preset
- Format-specific compression ratios
These estimates are calculated using constants fetched from the API and are typically accurate within 10-20%.
Sample Preview
Before committing to a full export, you can preview up to 5 images with your chosen settings:
- Configure your export settings
- Click Preview Sample
- Compare before/after side-by-side with zoom and pan
- Adjust settings and re-sample if needed
- Proceed to full export when satisfied
Samples are free — no credits are charged for preview exports. See Sample Preview for details.