How can I use Power Apps to rename this SharePoint image attachment?

In my canvas power app, I have a text input called ImageTextInput that I want to use to let users give an image a unique name as they upload it to a Sharepoint list. To store the name that the user types into the ImageTextInput box, I made a variable called imageName.

This power app gives my image attachment the name ".jpg" when I upload an image and type the name "MyImage" into the ImageTextInput box. The power app will name my image attachment "MyImage.jpg" if I upload a second image and enter "CoolImage" in the ImageTextInput box. In other words, it appears that the user-entered text is stored in the image Name variable before the image name is generated (using the Camera Control On Select code displayed below). How come?

Set(imageName,ImageTextInput.Text);
UpdateContext({showDialogBox: true});

Collect(
colImages,
{
DisplayName: imageName & ".jpg",
Id: imageName & ".jpg",
Value: Camera1.Photo
}
);

I also tried using the following code in the ImageTextInput field's OnChange and Onselect functions to ensure that the imageName variable is updated continuously, but that didn't work either. What can I do to make this image appear AFTER the user-entered text has been saved in the imageName variable? With no lag?

Set(imageName,ImageTextInput.Text);