Fix images with correct dimension and transparent parts

[nvborisenko]

Description

New images with smooth lines. Fixed sizes.

New sizes:

• 64
• 128
• 256
• 512
• 1024
• 2048

Checkmark is transparent. Should it be white?

Motivation and Context

My eye sees that image is not real square.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the contributing document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.