How can I transfer photos from a iPhone 3gs to a Windows10 pc

Try this > Connect your phone to the computer using the USB cable. Open File Explorer - the phone should appear on the left side as a device/folder. Expand the phone subfolders until you get to the folder containing the pictures. Select all the pictures and copy and paste them to a folder of your choice on your computer.

From this link that was from the link that TP provided you. http://windows.microsoft.com/en-us/windows-live/photo-gallery-import-photos-faq

No where does it indicate anything about iOS 8 here. You are just going to import the photos.

You can add photos to Photo Gallery by importing them from a camera, phone, or other
device, CD or DVD. Imported photos are stored in your My Pictures folder. You
can also add photos from an album on OneDrive, or from another location on your
PC.

To import photos from a camera, phone or other device, CD, or
DVD

1. Make sure that your device is turned on and connected to your PC, or that the disc is inserted into
your PC's CD or DVD drive.

1. Open Photo Gallery.
2. Click the Home tab, and then click Import.
3. In the Import Photos and Videos dialog box, click the
   device that you want to use, and then click Import. If you're importing
   from a CD or DVD, select the CD or DVD drive.
4. Click More options to select the options
   that you want to use, such as where to save the files and what format to use
   for the folder and file names.
5. Click one of the
   following two options: Review, organize and group items to import or Import all new items now.

Show all

Review,
organize, and group items to import

1. Click Review, organize and
   group items to import, and then click Next.
2. Define, select, and name
   the groups that you want to import:
   • Photos are automatically grouped according to when they were
     taken. To change the time interval used to define the groups, at the bottom of
     the window, move the Adjust groups
   • To choose which groups of photos to import, next to each group,
     select the check box.
   • To see all of the photos in a group, next to the group, click View all items. If you don't want to
     import all of the photos in the group, clear the check boxes for the photos
     that you don't want to import.
   • For each group of photos that you want to import, click Enter a name, and then type a name
     for the group.
   • To assign tags to a group, next to the group, click Add tags, type one or more tags
     separated by semicolons, and then press Enter.

Click Import. Each group of photos is saved to a different folder.

Import
all new items now

A 5 second Google search shows this: Import photos and videos from your iPhone, iPad, or iPod touch to your computer - Apple Support

Minik1959 wrote:

Thanks for that but everything we've tried requires iOS 8 or higher and we're only on iOS 6.1.6 on the iPhone 3GS :-(

That makes no difference whatsoever.