Fix: Updated image loading logic and implemented fallback renderer

[ShriramNarkhede]

Changes Made:

• Implemented fallback logic in load() to select image renderer based on availability.
• Added support for Imagick, GD, and native formats.
• Enhanced getRasterFormat() and getColumnFormat() with pixel conversion logic.

Why This is Needed:

• Previously, the code had unimplemented methods and default values.
• This PR adds actual logic for image loading and format conversion, making the class usable.

Notes:

• Ensures compatibility with common image types (e.g., PNG, BMP, PBM).
• Does not yet include full testing, as discussed.

Related Issues:

• None linked.