@gdsilva actually you can do it w/o any code it can be done trough the editor with your mouse but it’s a little tricky (to have 3 images side by side all centered), I’ll describe it from scratch (suppose you have a new page)
1. Click “Add media”, add the 3 images. By default they don’t have an alignment (when you click an image in the page editor, some icons appear and the 4th is “No alignment” and it is selected by defaul). If you would like to correct your page not starting from the beginning, just make sure you change the alignment icon for the 3 images to “No alignment”.
2. The secret (w/o this you can’t get the wanted result) – add some random text before the 3 images AND after them, you can add a single letter “a”.
3. Mark (select) everything with the mouse (the text at both sited and the 3 images) and click the text center icon in the icon bar in the editor tab (or press Shift+Alt+C). If you didn’t add some text this action would center the images (their align icons would change to “Align center” instead the default), something that is not wanted. BUT with the trick above, the text and images will get centered in a single line.
4. Now fix back the trick – just remove the text in the beginning and the end. As a result you will have the 3 images side by side and at the same time centered as a whole.
Note that this will result in a responsive layout – if you shrink the screen and there isn’t enough space the images will split and go to the next line if needed still centered.