[Updated September 1 2020]
Please refer to this blog post for details: https://community.esri.com/groups/survey123/blog/2020/08/07/survey123-tricks-of-the-trade-photos In short, you can use the multiline appearance on an image question to enable multiple photos on a single image question.
Hi Tony,
there are two approaches here that you can take:
1- Add multiple image questions in your form. Please note that Survey123 for ArcGIS will store your photos always as attachments, so technically no multiple fields are created in the feature service. I like this option the best because the photos get attached to your survey123 feature layer, making it very easy for you to look at your photos in web map popups. You can add as many image questions to a Survey as you like.
2- Use a repeat. You can add an image question within a repeat. Repeats are not my favorite approach, because photos are attached to a related table, making it very difficult to access the photos: you need ArcGIS Pro or ArcMap. However, with repeats you can let people take an unlimited number of photos.
Looking at upcoming enhancements, we want to support capturing multiple photos with a repeat without pushing the attachments to a related table. This will get the bests of repeats (unlimited photos) and adding image questions to your survey. We are looking at adding this functionality in either the September or October updates.
Ismael