Image MIME Reference
CLIP
Clip Studio Paint Document
image/vnd.clip
VS
Progressive JPEG (Legacy IE Alias)
image/pjpeg
PJPEG
A complete technical comparison of Clip Studio Paint Document and Progressive JPEG (Legacy IE Alias) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
PJPEG wins on browser support
Feature Support
| Feature | CLIP | PJPEG |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | Yes | ✕ No |
| Progressive Loading | ✕ No | Yes |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | Yes |
| ICC Color Profile | Yes | Yes |
Clip Studio Paint Document
image/vnd.clip
Extension
.clip.lip
Container
SQLite 3 Database
Compression
Proprietary Blob Compression (within SQLite)
Algorithm
Proprietary (Celsys Blob Encoding)
Color Depth
8-bit (Monochrome), 8-bit (Grayscale), 24-bit (RGB), 32-bit (CMYK)
Developed by
Celsys, Inc.
Released
2012
Magic Bytes
53 51 4C 69 74 65 20 66 6F 72 6D 61 74 20 33 00
Progressive JPEG (Legacy IE Alias)
image/pjpeg
Extension
.jpeg.jpg.pjpeg.pjp.jfif
Container
JPEG (ISO/IEC 10918-1)
Compression
Lossy (DCT)
Algorithm
Discrete Cosine Transform (DCT)
Color Depth
8-bit, 12-bit
Developed by
Joint Photographic Experts Group / Microsoft (Alias)
Released
1992
Magic Bytes
FF D8 FF E0 (JFIF) / FF D8 FF E1 (Exif)
Browser Support Comparison
| Browser | CLIP | PJPEG |
|---|---|---|
Chrome
|
✕ |
✓ All
|
Firefox
|
✕ |
✓ All
|
Safari
|
✕ |
✓ All
|
Edge
|
✕ |
✓ All
|
IE (Legacy)
|
✕ |
✓
|
CLIP
CLIP Strengths
- SQLite backend provides incredibly robust data integrity, preventing catastrophic project loss if the application crashes during a save
- Allows for massive multi-page comic projects and animation timelines to be handled efficiently without loading the entire project into RAM simultaneously
- Industry standard for manga, anime, and webtoon professional workflows
Limitations
- Heavily closed-source and proprietary, meaning no third-party applications (like ImageMagick or GIMP) can parse or render the files
- Standard MIME identification tools will misidentify the file as a generic SQLite database, causing friction in automated file-upload validations
- Zero web browser support
PJPEG
PJPEG Strengths
- Progressive JPEGs (which this MIME type attempted to describe) provide excellent perceived loading speeds on slow connections by rendering a low-resolution preview first
- Files sent with this MIME type are fully backwards compatible with any standard JPEG decoder
Limitations
- It is a non-standard MIME type that violates IANA specifications
- Causes strict file upload validation scripts to fail if not explicitly whitelisted or mapped
- Creates unnecessary confusion, as the official image/jpeg MIME type already fully encompasses progressive encoding
When to choose which format
CLIP
Use CLIP when…
- Digital Illustration and Concept Art
- Manga and Webtoon Production
- 2D Frame-by-Frame Animation
- High-Resolution Print Production
PJPEG
Use PJPEG when…
- Legacy Internet Explorer File Uploads
- Progressive Image Rendering (Historical context)