Yes, you can do that. You can easily restrict the types of media your guests can upload directly from your dashboard.
On desktop, go to "Event Settings" ("Settings" on mobile) in the left-side menu. Then, select the "Moderation" tab and find "Allowed Media Types". Tick only the media types you want guests to upload.
If you untick all options, no uploads will be allowed.
Note: This option is available only with the Plus and Pro Plans.