Why file size is reduced when an image is merged with a frame?

[Dianoban]

Why file size is reduced when an image is merged with a frame?

Computer: Desktop Windows 10 home 64b. 1803.
Camera: Sony a7ii with vintage prime lenses and Canon Rebel T6s with 18-135 zoom.
Image: Raw files (ARW & CR2)
Process: Raw files are processed in Camera Raw
Save as: Usually images are saved in PNG and JPEG.

Problem:
I make frames with Photoshop and save them in JPEG format, file size is usually 400kb~650kb. Sometimes, I have the processed images put in the frames. The file sizes of the images are reduced dramatically when the images are merged with the frame. Example, an image of 39.6mb saved as a PNG file is reduced to 5.48mb as the file size, together with the frame, though saved still in PNG format.

How the image & frame are merged:
1. Open a frame in Photoshop.
2. Place the image into the frame by Place Embedded and save as PNG format.
3. The file size now, image and frame together, is reduced to 12~14% of the original image size.

Question: Why the file size is reduced when a PNG image is merged with a JPEG frame?

Please help.

Thank you.
Dianoban

 

[IamSam]

Hello and welcome.

Your frame(s) may not be large enough for the images. If you are using place embed, Ps opens the image as a smart object ready for transforming. At this point, are you are resizing the image to fit within the frame?

If so, the now smaller resized image is merged with the frame and your saved file will also be smaller.

 

[Dianoban]

Hello and welcome.

Your frame(s) may not be large enough for the images. If you are using place embed, Ps opens the image as a smart object ready for transforming. At this point, are you are resizing the image to fit within the frame?

If so, the now smaller resized image is merged with the frame and your saved file will also be smaller.

Thank you.
May I ask, how to put a PNG image into a frame without losing the file size?
Any advice will be appreciated.
Dianoban

 

[JJLAPIN]

You say you build your Frames and they are 400kb~650kb. That is really small. Are they 72dpi? Build them at 300 dpi or whatever resolution your other files are and see what happens.

 

[IamSam]

May I ask, how to put a PNG image into a frame without losing the file size?

Reverse the process. You should open the image and then build the frame to fit the image.

Open the image and expand the canvas....


Set up center guides and use the Rectangle Tool to make a frame layer below the image layer.


Go to EDIT > TRIM > set to trim transparent pixels.



Now merge and save. You have not altered the size of the original image.

 

[Dianoban]

JJLAPIN
Thank you very much for the tip. I increased the size of the frame and the problem is solved.
Really appreciate your help.

Dianoban

 

[Dianoban]

Reverse the process. You should open the image and then build the frame to fit the image.

Open the image and expand the canvas....
View attachment 92972

Set up center guides and use the Rectangle Tool to make a frame layer below the image layer.
View attachment 92973

Go to EDIT > TRIM > set to trim transparent pixels.
View attachment 92974
View attachment 92975

Now merge and save. You have not altered the size of the original image.
View attachment 92976

Yes, IamSam. Adding a frame to an image definitely keeps the original file size of the image. But I do not want to do this every time a frame is needed.
As JJLAPIN points out, the file size of my frames are too small. I increased the size of the frame and the problem was solved immediately.
Thank you for your good will of helping me. Really appreciated.

Dianoban

 

[IamSam]

As long as your problem was solved, I'm happy!