Image Metadata Viewer: File Size, Dimensions & Color Depth

Image Metadata Viewer

An image metadata viewer reads the technical details stored in an image file without opening it in a photo editor. This tool reads a JPEG, PNG, or WebP file inside the web browser and shows its file name, file size, file type, last-modified date, pixel dimensions, aspect ratio, and color depth. The file is never sent to a server.

What information does this tool show?

After a file is uploaded, the tool lists these properties:

• File name — the name of the uploaded file.
• File size — shown in binary units (KiB, MiB, GiB), where each step is 1024 times the one before.
• File type — the file's MIME type, such as image/jpeg.
• Last modified — the modification date and time recorded by the operating system for that file. This is not necessarily the date the photo was taken; copying or re-saving a file can change it.
• Dimensions — the image's width and height in pixels, read by decoding the image in the browser.
• Aspect ratio — the width-to-height ratio, reduced to its simplest whole-number form.
• Color depth — the number of bits used to store each pixel, read from the file's header bytes.

What this tool does not show

Digital photos can also carry three other kinds of embedded metadata: EXIF (Exchangeable Image File Format), which cameras and phones write with details such as lens, aperture, shutter speed, ISO, and sometimes GPS coordinates; IPTC (International Press Telecommunications Council) fields, used by news organizations for captions, credits, and copyright information; and XMP (Extensible Metadata Platform), an Adobe format for editing history and custom tags.

This tool does not read any of the three. It cannot show camera settings, GPS location, copyright fields, or editing history, even when a file contains them. It only reads the seven properties listed above. Someone who needs EXIF, IPTC, or XMP data should use a dedicated tool such as ExifTool, or check a photo's details through their operating system's file properties panel.

How to calculate file size units

File size is measured in bytes and converted to the largest binary unit that keeps the number readable. The tool divides the byte count by 1024 repeatedly until the result is between 1 and 1024, then rounds to two decimal places:

1unit index = floor(log(bytes) / log(1024))
2size = bytes / 1024^(unit index)
3

The unit names are Bytes, KiB, MiB, GiB, TiB, and PiB. These are binary units where 1 KiB equals 1024 bytes and 1 MiB equals 1,048,576 bytes. This differs from the decimal KB/MB that some file managers use, where 1 KB equals 1000 bytes.

Example: a file of 2,500,000 bytes gives a unit index of 2 (MiB), so the size is 2,500,000 ÷ 1,048,576 ≈ 2.38 MiB, not 2.5 MB. The tool accepts files up to 50 MiB (52,428,800 bytes).

How aspect ratio is calculated

Aspect ratio is the width and height divided by their greatest common divisor (GCD), the largest number that divides both evenly:

1GCD(width, height)
2ratio = (width / GCD) : (height / GCD)
3

Example: for an image that is 1920 × 1080 pixels, the GCD of 1920 and 1080 is 120. Dividing both numbers by 120 gives 16:9.

How color depth is detected

Color depth is a property of the file's header, not of the decoded picture. A browser always decodes an image into 8-bit-per-channel pixels internally, even if the source file used a different depth. To report the real value, the tool reads the raw bytes of the file itself instead of the decoded image:

• PNG: the IHDR chunk stores a bit-depth byte and a color-type byte. Bit depth is bits per sample, so the tool multiplies it by the number of channels the color type implies.
• JPEG: a start-of-frame marker stores the sample precision and the number of color components; bits per pixel is precision × components.
• WebP: the VP8X, VP8, or VP8L chunk indicates whether the image has an alpha channel, giving 24 bpp (RGB) or 32 bpp (RGBA).

Example: a standard JPEG photo with 8-bit precision and 3 color components (YCbCr) reports as 24 bpp (8 bits/channel, YCbCr). If the file's header cannot be matched to one of these three layouts, the color depth field is left out of the results.

Supported file formats

The tool accepts JPEG, PNG, and WebP files. Other formats, including GIF, TIFF, HEIC, and RAW camera files, are not accepted by the uploader.

How to use the tool

1. Click the upload area, or drag and drop a JPEG, PNG, or WebP file onto it.
2. The tool decodes the file locally and lists its metadata in a table.
3. Click "Copy" next to any row to copy that single value.
4. Click "Download Metadata" to save all the values as a text file.

Everything happens in the browser using JavaScript's FileReader and Image APIs. No file is uploaded to a server at any point.

Example

Uploading a JPEG photo that is 1920 × 1080 pixels and 2,500,000 bytes, saved with 8-bit YCbCr encoding, produces:

Frequently asked questions

Does this tool show GPS location or camera settings? No. Those come from EXIF data, and this tool does not read EXIF segments. It only reports file name, size, type, last-modified date, dimensions, aspect ratio, and color depth.

Is my image uploaded to a server? No. The file is read and decoded entirely inside the browser using JavaScript. It never leaves the device.

Why is my file size shown in MiB instead of MB? The tool uses binary units (1 KiB = 1024 bytes) rather than decimal units (1 KB = 1000 bytes). The "i" in the name marks a binary unit.

Why doesn't the color depth field appear for my image? Color depth is only reported when the file's header matches a known JPEG, PNG, or WebP layout. If the header can't be parsed, the field is left out rather than showing a guess.

Why doesn't the "last modified" date match when the photo was taken? That date comes from the operating system's file-modification timestamp, not from the camera. Copying, re-saving, or transferring a file can change it, and it can differ from any capture date stored in EXIF data (which this tool does not read).

Can I upload a GIF, TIFF, or RAW file? No. The uploader only accepts JPEG, PNG, and WebP files.

References

1. National Institute of Standards and Technology (NIST). Prefixes for binary multiples. NIST: binary prefixes — kibi (Ki) = 2^10 and mebi (Mi) = 2^20; 1 MiB = 1,048,576 bytes versus 1 MB = 1,000,000 bytes.
2. World Wide Web Consortium (W3C). Portable Network Graphics (PNG) Specification (Third Edition). PNG specification — the IHDR chunk holds a one-byte bit depth (bits per sample) and a one-byte color type.
3. International Press Telecommunications Council (IPTC). IPTC Photo Metadata. IPTC Photo Metadata — the standard for administrative, descriptive and copyright information about images.