WordPress galleries are a good way of displaying photographs and provided that your original photographs are of good quality, you should see good clear images on the screen.
If you are using the Block Editor (default) you can refer to this description for adding a gallery in Easy WP Guide. If you are using the Classic Editor, the way to add a gallery is first to Insert Media and then from the media screen to Create New Gallery.
There are a couple of things to note.
Viewing Full Size Images
A gallery will normally show an array of small images and you can click on any one image to view the full size version. To make this full size view happen you need to change the Link To setting to Media File.

Adding Pictures to an Existing Gallery
Click on the gallery and at the bottom you should see a button to take you to the Media Library.

Click on that and you’ll get to a list of media items you can add.
NOTE: There is an annoying bug in recent versions WordPress, and if you add items straightaway you’ll lose the existing gallery content. It’s still in the media library but you’ll need to add it back in again. The workaround is first to click on Edit Gallery, which will show the existing content, and then click on Add to Gallery.

Members Portrait Gallery
If you want to show a set of headshots of the ministry team, a gallery is a good way to lay these out. However it doesn’t work well in the block editor if the number of images is not a multiple of the number of columns. For example if you have seven team members and you’re showing three columns, you’ll get two rows of three and a single photo on the last row.
With the block editor, every row is made the same size and the photo size is adjusted to fit, so that last single photo will appear three times as big as the others. This works quite well with photographs from an event, but not for headshots.
In order to prevent this last row from being automatically resized you need to use the Advanced settings to add an Additional CSS class as shown below.

Rotated images
Occasionally images appear rotated in your library. If this happens, you can fix it after the image has been uploaded.
In the Media library, click on the image that you need to fix. Underneath you should see an Edit Image button. Click that and you go to the Editor page.

When you have corrected the orientation, just click the Save button.
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