Image sizing

[rich2005]

Quote:...I am a watercolour artist and I paint various elements to be included in a fabric pattern, the size of the patter is 8inches x 8inches.  When I take a photo of each image to put into Gimp they are all 3024 x 4032 or 42 inches x 56 inches...

ref: https://i.imgur.com/7X6hw2e.jpg
Gimp and your camera work in pixels not real world  (inches / millimetres etc) units. Open up your photo in Gimp then go to  Image -> Print Size and you will see  something like
Top of the Gimp window the size in pixels (1)
The Image Print resolution. The pixels-per-inch (ppi) is 72 Units in inches 42 x 56 (2)

If you want that square, then you will have to crop-out part of the image. Crop Tool (3) Set the aspect ratio to fixed and 1:1 (4) and size up the tool on the canvas to what you require as a tile. (5) Hit the enter key or click inside the square to complete.

ref: https://i.imgur.com/cop6U6Z.jpg
You now have a square and for printing that might be set to any ppi you like. However for the sake of tidyness you might want to scale the image to a ppi of 300 This is a rule of thumb for photographic quality (although for various circumstances it can be less) The magick number here is to end up with a square 2400 x 2400 pixels (6)  2400 pix @ 300 ppi = 8"

Seamless tiles: This can be a bit of a dark art and involve much editing by hand or the Gimp Seamless tile tool Filters -> Map -> Tile Seamless (7) might work out-of-the-box. All depends on image you made.

Exporting the image (png or jpg) to the Gimp patterns folder and filling a Gimp A4 size canvas looks like this: https://i.imgur.com/7rlfjGf.jpg

Post one of your photos (use dropbox or similar) and you might some considered advice.

Quote:..When I open a new file and make it 8inch x 8inch the images dont fit on to them. ..

You must start off with a suitable canvas. Gimp 2.10 now tends to default to 300 ppi as above but if you are still using Gimp 2.8 it will be 72 ppi and much too small in pixels. 8" @ 72 ppi is only 576 pixels. Printing quality will be awful. Make a canvas 2400 x 2400 pixels If copy pasting then you might still have some scaling to do but not so much.

edit: Oh...I see from your previous post you are using a Mac - then probably Gimp 2.8 and that 72 ppi default resolution.
Make a new canvas like this: Set the X / Y resolution first, then set the width / height size in pixels or inches.