How can I transfer photos from my IPhone to my desktop computer?

[Bill]

Hi,

I am having problems accessing photos from my IPhone.  I am using Mint 
with the Mate GUI. Here is what I have done.

1. I connected my IPhone to my desktop computer with a USB cable.

2. My desktop shows the IPhone has been mounted.

3. On my IPhone, I entered the password when prompted.

4. On my desktop, The PIx program starts and shows the pictures 
directory where the photos (on my desktop computer) should be put.

5. When I press OK, nothing happens.

It looks like the security on the IPhone or maybe Linux (or both) is 
interfering with the transfer.  What should I do?

Bill Stanley