I want to second this request. I think the issue AvinashR linked to above is similar, but not the same as the one being reported here. My workflow looks like this:
During the day I'll take photos of anything I want to journal about. Let's say for argument that on September 1st at 10am I take a picture of my kids doing something cute.
Later, often on a different day (maybe September 2nd or 3rd at 7:30pm), I'll add the photos to Diarium and write an entry about them. I do this by opening the photos app on iOS, click the share icon, and choose "Diarium". Diarium will open and ask me what entry I'd like to attach the content to. The DATE OF THE PHOTO IS AUTOMATICALLY SELECTED (this is a GOOD thing). However, when I click "add" the time of the entry is the current time, even though the date is that of the photo, which can be (and often is) different. So in this example I'm writing about something that happened September 1st at 10am. However, the app will automatically set the date and time to be September 1st at 7:30pm, so the date is correct and matches the photo, but the time does not, so my entry doesn't match the time of the photo OR the current date - it's the worst of both worlds. I then have to edit the date and time of my entry to match the time in the photo.
I understand defaulting to the current time when you create an entry from scratch, but when you import a photo, especially on a different date, it makes much more sense to use the time from the photo. If you're worried about breaking current users' workflow, add a dialog that, on importing a photo, asks if they want to use the date AND TIME from the photo. This was the behavior on other apps I've used (i.e. Journey), and was much more convenient.