I need make some basic image editing, preferably in nondestructive way. I have template with guidelines and image (.tif), I opened both as separate layers. I need crop rectangular selection from image and place it into the template. Should I trim image or make selection, copy and paste it into the template? Also, I want make rectangular selection on template and fill it with pattern. How to make this?

The first thing to consider is your template. Is it for printing? Is it a suitable size in pixels and ppi?

I think you will be better off opening the template and images separately.

Select and copy in the image and paste-as-a-new-layer in the template. That way is more-or-less non-destructive.

The pasted layers can be moved around the template and if View -> Snap to guides is on will do that, snap to a guide.

Pasted selection too large? It can be cropped, the crop tool will also snap to guides. Make sure current-layer-only is enabled. see first attachment.

Pasted too small? The pasted layer can be scaled in place and after scaling cropped if required. see second attachment.

Finished result is third attachment, but final comment, there are other better ways of making a, using layer masks.

rich: www.gimp-forum.net

I need make some basic image editing, preferably in nondestructive way.

Only fair to give an example using layer masks

The same image in separate layers and positioned according to the template.

Layer masks applied to define the viewable areas. see attachment

Nothing edited in the images, non-destrucive.

some info here: https://www.gimp.org/tutorials/Layer_Masks/

rich: www.gimp-forum.net

Printing template for preparing artwork. I need extend background pattern up to green bleed line. Existing artwork size is inside rounded rectangle and should be used 1:1, without scaling/expanding.

1. Printing size

Gimp will import a PDF at 100 ppi by default. The PDF properties indicate that the size is 124 mm x 92 mm (biz card maybe). For printing quality, open the PDF with a ppi of 300

2. A template

Attached. Opens straight up in Gimp. Put your image on the bottom layer. Turn off visibility on the top layer before exporting to whatever format your Printing Company requires. (TIFF, jpeg ..)

rich: www.gimp-forum.net

Attached is image sample, its 600dpi. It's a bit tricky: I need retain existing image resolution and size of all artwork and text inside that rounded card, the size of image is a little smaller than the size of green bleed line. So, in order to get edge to edge printing, I want extend only backround to all 4 sides of image to cover bleed line.

Oh dear, this is what happens with no planning. Good in one way, your image has a resolution of 600ppi, a little over-the-top but better than too low a value. For sending to a printer 300 ppi is suitable unless they ask for more. Leave it as 600 ppi and see what happens.

always a but...

You will be better off starting from scratch using all the tools that Gimp provides, layers, layer-mask, gimp guides, selections. Trying to modify the existing image will end up, less than wonderful.

The patterns are standard Gimp, sky and pine, however the sky pattern does not extend outside the 'safe area' and the other colours and pattern do.

Attached, is a scaled up to 600 ppi template with the image recreated. If you turn on the guides, View menu -> Show Guides, you will see, plenty of them. Get in the habit of using them. These only exist in Gimp, they are not printed.

For adding text, put your text layers under mask layer, there is one there already as an indicator.

When complete and ready for printing, turn off the visibility of the top layer. That will leave only the crop marks used by the printer. Rounded corners are part of the printing process, cut out by the printing company.

rich: www.gimp-forum.net

Thank you for the help. I need copy a lot of elements from original image to new image in template: should I paste every element as new layer?

As with everything, it depends, but at least one layer, separate from the background layers.

For logos and small graphics in a fixed position could go on a single layer.

The advantage of using separate layers is individual elements can be adjusted, moved, scaled, rotated without disturbing anything else.

Text is best kept as a text layer. If you try and copy-paste from another image it will end up rasterized. Always best to try and recreate.

rich: www.gimp-forum.net