Add the GMT/PyGMT preworkshop at AGU24 to the "External resources" section

[yvonnefroehlich]

Description of proposed changes

Add the GMT/PyGMT preworkshop at AGU24 to the "External resources" section:

• Create and add thumbnail image (similar to the egu2022 workshop, see Add thumbnail images to the external resources page #1941)

Preview: https://pygmt-dev--3689.org.readthedocs.build/en/3689/external_resources.html

Fixes: #3683 (partly)

Reminders

• Run make format and make check to make sure the code follows the style guide.
• Add tests for new features or tests that would have caught the bug that you're fixing.
• Add new public functions/methods/classes to doc/api/index.rst.
• Write detailed docstrings for all functions/methods.
• If wrapping a new module, open a 'Wrap new GMT module' issue and submit reasonably-sized PRs.
• If adding new functionality, add an example to docstrings or tutorials.
• Use underscores (not hyphens) in names of Python files and directories.

Slash Commands

You can write slash commands (/command) in the first line of a comment to perform
specific operations. Supported slash command is:

• /format: automatically format and lint the code

[seisman]

@yvonnefroehlich It seems the thumbnail image for the "PyGMT-Howto" tutorial is also broken. Please help fix it in this PR.

[yvonnefroehlich]

@yvonnefroehlich It seems the thumbnail image for the "PyGMT-Howto" tutorial is also broken. Please help fix it in this PR.

The URL is updated in commit cdcc26e.

[yvonnefroehlich]

[seisman]

I just downloaded the image and upload it again. Here is the link I have:

https://github.com/user-attachments/assets/f92e1391-78f4-41bc-8ed8-5df1f59b8362

[seisman]

Looks good to me.

[weiji14]

Thanks for adding this @yvonnefroehlich!

[weiji14]

Could we have a slightly taller screenshot?

Suggested change

	
	

[yvonnefroehlich]

I also prefer to show the figure of Tutorial 4 completely, but there is already quite a lot white space when using the current screenshot in the neighboring cards, so I was unsure using a taller screenshot. But let's try and see how it looks.

screenshot with cut Tutorial 4	screenshot with complete Tutorial 4

[seisman]

What about this one? The title is removed from the screenshot.

https://github.com/user-attachments/assets/b86fd4c1-c5dd-4d51-a7fe-362d86cc01b0

[yvonnefroehlich]

Actually, I thought about not including the title in the screenshot, but kept it to be consistent with the image for the EGU2022 workshop. But let's see how it looks after 2e8b38e:

screenshot with cut Tutorial 4	screenshot with complete Tutorial 4	screenshot without title

[seisman]

I think you can choose anyone you like, then merge this PR.