Convert JPG to JPEG
JPG and JPEG are the same format. Re-encode with optimized compression and the .jpeg extension.
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JPG vs JPEG: The Extension Difference
Identical Format
JPG and JPEG use the same compression algorithm. Only the file extension differs.
Re-optimization
Re-encoding can optimize compression and potentially reduce file size.
Compatibility
Some systems prefer the .jpeg extension. This tool ensures the correct naming.
Quality Slider
Fine-tune the output quality to balance file size and visual fidelity.
When .jpeg Is the Required Extension: Standards Compliance and Cross-Platform Consistency
While the web standardized on .jpg, several professional and scientific ecosystems mandate the full .jpeg extension. The MIME type registered with IANA is image/jpeg — not image/jpg — and standards-strict software often expects the extension to match. DICOM medical imaging workflows, certain GIS mapping tools, and academic publishing platforms specifically validate for .jpeg, rejecting .jpg files at the upload stage even though the binary content is identical.
Adobe's Creative Cloud ecosystem historically used .jpeg as its default save extension on macOS, creating a split where designers on Mac produced .jpeg files while Windows-based teams generated .jpg. When these assets converge in a shared DAM (Digital Asset Management) system, inconsistent extensions break automated thumbnail generation, version tracking, and metadata indexing. Normalizing to .jpeg before ingestion into these systems prevents cascading failures.
The JPEG committee's official specification (ITU-T T.81) does not mandate any particular file extension, leaving the decision to operating systems and applications. However, the JFIF (JPEG File Interchange Format) documentation references .jpeg as the canonical extension. For archival purposes and long-term digital preservation — where adherence to original specifications matters — .jpeg is the technically correct choice, which is why the Library of Congress and similar institutions prefer it.
Converting from .jpg to .jpeg in Krunkit is a zero-loss operation that modifies only the filename metadata. No pixel data is decoded, processed, or re-encoded. The file's binary content, EXIF metadata, ICC color profile, and embedded thumbnails remain completely untouched. This makes it safe for batch processing thousands of archival images without any risk of generational quality degradation.
Pro Tips
Check your target platform's extension requirements before batch converting
Medical imaging systems (DICOM), certain academic journals, and government digital archives often enforce .jpeg specifically. Verify the exact requirement before processing — some systems check MIME type instead of extension, making the rename unnecessary.
Use .jpeg for macOS-centric workflows to match system conventions
macOS Preview, Photos, and many native apps default to .jpeg. If your team works primarily on Apple hardware, standardizing on .jpeg reduces friction when files move between Finder, iCloud, and Adobe tools that respect the macOS convention.
Preserve EXIF data during the extension change
Some tools strip EXIF metadata when 'converting' between .jpg and .jpeg because they silently re-encode. Krunkit's approach is a pure rename — EXIF fields including GPS coordinates, camera model, exposure settings, and copyright notices remain intact.
Frequently Asked Questions
Is there any difference between JPG and JPEG?
No. They are the same format — JPEG is the full name, JPG is the shorter extension from DOS-era limitations.
Does this actually convert anything?
The image is re-encoded with optimized compression, which can reduce file size. The format itself doesn't change.
When would I need a .jpeg extension?
Some platforms, APIs, or content management systems specifically require the .jpeg extension.
Is this free?
Yes, completely free with no limits. Runs in your browser.