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Error Code Reference

Every error the LSB steganography tool can emit is listed here. When something goes wrong the tool prints a line of the form:

[Exx] Human-readable description of the problem.

Use the code (xx) to find the relevant entry below.

Quick-reference table

Code Short name When it occurs
E02 Invalid arguments Neither -E nor -e was given, or required arguments missing
E03 Image not found The source image path does not exist
E04 Embed file not found One or more files passed to -f do not exist
E05 Image too small The payload exceeds the image's embedding capacity
E06 Wrong password Hash mismatch — wrong password or no data in the image
E07 Image load error The image file is corrupt, truncated, or in an unsupported format
E08 Write error An output file could not be created or written
E10 Internal error An unexpected internal state was reached (bug)

Detailed entries

E02 — Invalid arguments

Message: No mode selected. Use -E/--embed to embed files or -e/--extract to extract. (argparse also uses exit code 2 for unrecognised or missing required flags.)

Cause: The tool was invoked without specifying what to do, or a required argument (such as -i or -p) was omitted.

Fix: Run lsb-tool --help (or python -m lsb_tool --help) to see all options. At minimum you need:

# Embed
lsb-tool -E -i image.png -p password -f file_to_hide.txt

# Extract
lsb-tool -e -i image.png -p password

E03 — Image not found

Message: Image file '<path>' not found.

Cause: The path supplied with -i does not point to an existing file.

Fix: Verify the path with ls (or dir on Windows). Check for typos, missing directories, or incorrect working directory.

E04 — Embed file not found

Message: File to embed not found: '<path>'

Cause: One or more of the files passed to -f do not exist at the given paths. All files must exist before the tool starts writing to the image.

Fix: Check the path(s) for typos. All files listed after -f must be readable before running the tool.

E05 — Image too small

Message:

The files are too large to embed in this image at depth <N>.
  Required : X bytes
  Available: Y bytes
  Try a larger image, increase the depth with -l, or embed fewer files.

Cause: The total payload (header + filenames + file data) does not fit within the embedding capacity of the image at the chosen depth.

The capacity formula is:

available = (total_pixels - preamble_pixels) × channels × depth ÷ 8   bytes

Increasing depth multiplies capacity proportionally, at the cost of visible degradation (each extra bit modifies higher-order bits in each channel).

Fix — in order of preference:

  1. Increase the depth (-l 2, -l 4, …). Each step roughly doubles capacity. Do not exceed the image type's channel bit-depth (8 for standard PNG, 16 for 16-bit grayscale).
  2. Use a larger image. Capacity scales with the number of pixels.
  3. Reduce the payload. Compress files before embedding, or split them across multiple carrier images.
  4. Reduce the filename field. A large -n value reserves space per file. Set it to 0 if stored filenames are not needed.

E06 — Wrong password

Message:

Could not verify the embedded data.
The password may be incorrect, or this image contains no hidden files.

Cause: The 512-bit verification hash stored in the image does not match the hash derived from the supplied password. This happens when:

  • The password is wrong.
  • The image was not created with this tool (or was created with a different version that used a different format).
  • The image was modified after embedding (e.g. re-saved as JPEG, which is lossy and destroys the embedded bits).

Fix:

  • Double-check the password. Passwords are case-sensitive.
  • Make sure you are using the same image that was produced by the embed step (the _embedded.png file, not the original).
  • Ensure the image was not converted to a lossy format between embed and extract. Always use PNG.

E07 — Image load error

Message:

Could not open '<path>' as an image. The file may be corrupt,
truncated, or in an unsupported format.

Cause: The Pillow library could not decode the file. Common reasons:

  • The file is not an image (e.g. a text file with a .png extension).
  • The file is partially downloaded or otherwise truncated.
  • The image is in a format Pillow does not support (e.g. HEIC without the heif plugin).

Fix:

  • Verify the file opens correctly in an image viewer.
  • Convert the image to PNG with any standard tool (ffmpeg, GIMP, ImageMagick) before using it as a carrier.
  • Check that the file transfer completed without errors.

E08 — Write error

Message: Could not write '<filename>'. Check that you have write permission in the current directory.

Cause: An extracted file (or the output _embedded.png) could not be created. Common reasons:

  • No write permission in the current directory.
  • A directory with the same name already exists.
  • The disk is full.
  • The filename decoded from the image contains characters that are not valid on the current OS (unusual but possible with filenames embedded on a different operating system).

Fix:

  • Run the tool from a directory you have write access to.
  • Check available disk space.
  • If the conflict is a filename collision, rename or move the conflicting file first.

E10 — Internal error

Message: An internal error occurred (<detail>). Please report this as a bug.

Cause: The tool reached a code path that should be unreachable under normal operation. This is a bug.

Fix: Please open an issue and include:

  • The exact command you ran.
  • The full error output (including the [E10] line and any Python traceback).
  • The OS, Python version (python --version), and Pillow version (python -c "import PIL; print(PIL.__version__)").