DOC: Reduced main image size

[viv511]

Scaled original image by 50% in height and width. Changed because original image was too large.

Closes PR #4785

PR Checklist

• No API changes were made (or the changes have been approved)
• No major design changes were made (or the changes have been approved)
• Added test (or behavior not changed)
• Updated API documentation (or API not changed)
• Added license to new files (if any)
• Added Python wrapping to new files (if any) as described in ITK Software Guide Section 9.5
• Added ITK examples for all new major features (if any)

Refer to the ITK Software Guide for
further development details if necessary.

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[jhlegarreta]

IMO the image should have a fixed size: what if a new version of the logo that has a different size is added?

[viv511]

Hi! Sure, I can add a new version of the logo with a different size. I used a HTML/CSS fix as per discussion in the original issue thread

[jhlegarreta]

Hi! Sure, I can add a new version of the logo with a different size. I used a HTML/CSS fix as #4785 (comment) in the original issue thread

I did not mean that we would need to add a logo with a different size; the issue probably arised because the new logo is much larger than the previous one, and if the situation repeats in the future the 50% width/height solution may be problematic. So IMO ideally we want the size of the displayed image be always the same (or have a fixed width or height, to respect its aspect ratio), regardless of the size of the logo in the original file.

[dzenanz]

ITK's logo does not change frequently. This PR improves the situation. Further improvements can be done in a follow-up PR, and/or when the logo is changed again.