How to Work with PSD Image Resources in Python

A loaded PsdImage exposes its image resource blocks — metadata-style entries such as grids, guides, and ICC profile payloads — through two read-only views, plus a separate summary for indexed color palettes.

Step-by-Step Guide

Step 1: Install the Package

git clone https://github.com/aspose-psd-foss/Aspose.PSD-FOSS-for-Python.git
cd Aspose.PSD-FOSS-for-Python
# No packaging manifest is published yet -- run from this folder,
# or add it to PYTHONPATH:
export PYTHONPATH=$PWD:$PYTHONPATH

Step 2: Import Required Classes

from aspose_psd_foss.psdimage import PsdImage
from aspose_psd_foss.resources.imageresourceids import ImageResourceIds

Step 3: Check and Count Image Resources

image = PsdImage.load("input.psd")

print(f"Has image resources: {image.has_image_resources}")
print(f"Resource count: {image.resource_count}")

Step 4: List Resource Blocks via `image_resources`

PsdImage.image_resources returns a PreservedResourceBlock per resource, with the raw resource ID, name, and byte size:

for block in image.image_resources:
    print(f"ID: {block.id}, name: {block.name!r}, size: {block.size} bytes")

Recognize a specific resource by comparing block.id against the known constants in ImageResourceIds:

for block in image.image_resources:
    if block.id == ImageResourceIds.ICC_PROFILE:
        print(f"Found an ICC profile resource ({block.data_size} bytes)")

This FOSS build’s resource parser does not decode resource IDs into semantic properties itself — comparing block.id against ImageResourceIds yourself is the supported way to recognize a specific resource.

Step 5: List Resource Summaries via `resources`

PsdImage.resources returns a separate PsdResourceInfo summary per resource, including a kind classification:

for info in image.resources:
    print(f"ID: {info.resource_id}, kind: {info.kind}, data length: {info.data_length}")

In this FOSS build, kind is always PsdResourceKind.UNKNOWN — semantic classification of specific resource kinds (global angle, ICC profile) is not implemented, so treat kind as informational only and rely on resource_id (Step 4) to recognize a specific resource.

Step 6: Read an Indexed Color Palette

If the document’s color data is palette-based, PsdImage.indexed_palette returns its entries:

palette = image.indexed_palette

if palette is not None:
    print(f"Palette entries: {len(palette.entries)}")

Common Issues and Fixes

image.indexed_palette is None. The document’s color data kind is not INDEXED_PALETTE — only indexed-color documents carry a palette.

Setting image.image_resources raises NotSupportedException. The getter works for listing resources, but the setter is not supported in this FOSS build.

Calling block.save() on a PreservedResourceBlock raises NotImplementedError. Saving individual resource blocks directly is not supported — resources round-trip automatically when you call image.save() on the whole document.

has_icc_profile, is_icc_profile_untagged, and global_angle never change. These three PsdImage properties are fixed placeholder values in this FOSS build (has_icc_profile is always False, is_icc_profile_untagged is always None, global_angle is always 0) regardless of the loaded document’s actual content — this build’s resource parser does not reconstruct ID-specific semantic values. Use Step 4’s block.id comparison against ImageResourceIds if you need to detect these resources yourself.

Frequently Asked Questions

What’s the difference between `image_resources` and `resources`?

Both list the same underlying resource blocks, but as different object types: image_resources returns PreservedResourceBlock objects (raw ID/name/size, used for round-tripping), while resources returns PsdResourceInfo summaries (adds a kind classification, currently always UNKNOWN).

Can I modify or remove an image resource?

No — image_resources’ setter raises NotSupportedException, and PreservedResourceBlock.save() raises NotImplementedError if called directly. Resources are read-only in this FOSS build.