Image sizing recommendations

The docset should include content on ensuring that images are loading for the correct size for their use case, with links to Apple/Google/Windows docs that describe sizes and styles. For example, Apple has different recommendations if the image is square, round, portrait or landscape. All the sizes are slightly different. And even though Android and Windows look correct, they are in fact loading a huge image and resizing it after the fact.

This should include tabs, menus, toolbars, other icons, and images in general.

As background, see https://github.com/dotnet/maui/issues/8609

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#### Document Details

⚠ *Do not edit this section. It is required for learn.microsoft.com ➟ GitHub issue linking.*

* ID: 7d7dc547-5ff1-416d-450b-e39e56cb1e71
* Version Independent ID: 7d7dc547-5ff1-416d-450b-e39e56cb1e71
* Content: [Add images to a .NET MAUI app project - .NET MAUI](https://learn.microsoft.com/en-us/dotnet/maui/user-interface/images/images?view=net-maui-7.0)
* Content Source: [docs/user-interface/images/images.md](https://github.com/dotnet/docs-maui/blob/main/docs/user-interface/images/images.md)
* Product: **dotnet-mobile**
* Technology: **dotnet-maui**
* GitHub Login: @davidbritch
* Microsoft Alias: **dabritch**