Batch Image Format Checker
Inspect up to 30 files and identify common image formats from their byte signatures rather than trusting filenames alone. Compare the detected format with each extension and browser-declared MIME type, flag mismatches, and download the complete local report as CSV.
- Local processing
- No account required
- Per-file status
- Free to use
Built for dependable batch work
The checker recognizes common PNG, JPEG, GIF, WebP, AVIF, BMP, TIFF, ICO, and SVG signatures. It is a triage tool, not a complete security scanner, malware detector, codec validator, or guarantee that every recognized file will decode correctly in every application.
Checks bytes, not just names
Built for repeatable image workflows with clear output evidence.
Flags extension mismatch
Your selected files remain in the current browser session.
Supports common web formats
Each queue row reports its own result without blocking valid files.
No image upload
Downloadable output uses names and formats that match the generated bytes.
How to use Batch Image Format Checker
A four-step workflow keeps the original files separate from generated output.
- 1
Add files
Choose up to 30 suspected image files.
- 2
Choose settings
Run signature inspection in the browser.
- 3
Process locally
Review detected type and mismatch flags.
- 4
Verify and download
Download the CSV for inventory or remediation work.
What this batch tool does
The checker recognizes common PNG, JPEG, GIF, WebP, AVIF, BMP, TIFF, ICO, and SVG signatures. It is a triage tool, not a complete security scanner, malware detector, codec validator, or guarantee that every recognized file will decode correctly in every application. Every item is handled independently, so one unsupported or damaged file does not erase successful work from the rest of the queue.
- Checks bytes, not just names
- Flags extension mismatch
- Supports common web formats
- No image upload
Batch Image Format Checker guide
Use these checks to get output that fits the destination rather than stopping at a successful download.
Why signatures are more useful than extensions
A filename extension is a label that can be changed without touching the file. Most binary image formats begin with identifying bytes or contain a required brand near the beginning. Reading those values gives stronger evidence of the actual container. This tool compares that evidence with the visible extension and browser MIME declaration so mislabeled assets stand out quickly.
Interpret a mismatch carefully
A mismatch can come from an accidental rename, a server export bug, a misleading download, or a MIME declaration based only on the filename. It does not automatically mean the file is malicious. Preserve the original, inspect it with trusted software, and convert it properly if another format is needed. Renaming .png to .jpg does not create JPEG bytes and should not be used as a repair.
Understand recognition limits
Signature recognition identifies the container family, not whether every internal chunk, frame, color profile, or compressed stream is valid. SVG is text-based and is recognized from initial markup, while complex XML wrappers may require deeper parsing. New or specialized formats can appear as unknown. A recognized AVIF or TIFF can still be unsupported by the current browser decoder.
Use the CSV as an asset audit
The report records source name, browser MIME type, extension, detected format, byte size, and status. It can support a content migration, media-library cleanup, quality-assurance review, or handoff to a conversion workflow. Treat unknown and mismatched rows as items for review, not automatic deletion. Keep a controlled original set until replacement assets are tested at their destination.
Batch quality checklist
Start with copies when the source collection is valuable, and keep filenames that let you trace every result back to its original. Test a small representative set before processing the full queue, including the largest file, a transparent image, a portrait, and a landscape image. After processing, compare pixel dimensions, format, file size, transparency, text sharpness, edge detail, and color in the actual destination. A successful browser status confirms that this tool completed and verified its expected output structure; it does not replace editorial review or the receiving platform’s rules. Keep the downloaded ZIP or CSV with the settings used for the run, then record exceptions that need individual treatment. For publishing workflows, also check descriptive alternative text, rights, consent, naming conventions, backup policy, and cache behavior. These steps make a repeatable batch safer than treating every completed download as automatically ready for production.
Frequently asked questions
Practical answers about formats, privacy, quality, and browser behavior.
Does the checker trust the filename extension?
No. It reads identifying bytes first and compares the result with the extension and browser MIME declaration.
Can renaming an extension convert an image?
No. A real conversion must decode and encode the target format; changing the name only changes a label.
Which formats can be recognized?
PNG, JPEG, GIF, WebP, AVIF, BMP, TIFF, ICO, SVG, and unknown are reported.
Does recognized mean the image is valid?
Not necessarily. Signature detection does not fully validate every structure or compressed data stream.
Is this a malware scanner?
No. It is a format triage tool and should not replace security scanning or trusted file handling.
Are files uploaded?
No. The browser reads a small local byte sample and creates the report locally.
Can I export the findings?
Yes. After checking, download a CSV containing every row and mismatch status.