Yes, undoubtedly a presentation with relevant pictures is more effective than plain text slides. However, even if pictures enhance appearances, they can also phenomenally increase the size of your presentation file. Picture compression can help. Recent versions of PowerPoint do some automatic picture compression, even if you are not aware. There are options to make any such compression even more effective.
Microsoft and the Office logo are trademarks or registered trademarks of Microsoft Corporation in the United States and/or other countries.