PSD same res but huge file size difference

[cpt63921924]

Hi everyone, I have this puzzling question I like to find an answer to.

I have 2 PSDs of the same size and dpi but their file size are hugely different (188kb vs 30mb). Why is this so?

The file description are as follow:

:: Image A (188kb) ::

2.6cm x 2.6cm, 300dpi, greyscale, 8bit, Transparent background. Only one layer, unflattern.
Image on the layer is a thin circle line with a "X" inside. No smart object or vector inside this PSD.

:: Image B (30mb) ::

2.6cm x 2.6cm, 300dpi, greyscale, 8bit, Transparent background. Only one layer, unflattern.

Image on the layer is a thin circle line with a "Y" inside. No smart object or vector inside this PSD.

To summarize both are circle logo on a transparent layer, unflattern. I have no idea why their file size are so different. Can someone explain?

Thank you

[JJMack]

How many layers do each have one how many smart object object layers with embedded objects the are copies of other files. Size and resolution is only a small factor.  Content is the biggest factor. Even without smart object images compress varies bat image content.  Not by Numbers of Pixels in a image. There is also metadata,  30MB would seem very big if you have only one image. However the image may have megabytes of old history metadata.

https://forums.adobe.com/search.jspa?q=remove+ancestor+metadata&place=%2Fplaces%2F1413024

If you dupe the large PSD as many times as it has layers and delete different  layers in each save them you may fine one layer is causing the bulk of the file size.  If all save 30 MB I would suspect ancestor metadata.

[cpt63921924]

Thank you for the tip JJMack,

I notice the larger PSD has a very messy raw data code, while the smaller file size is clean and simple.

I have uploaded the two PSDs online, PSD.zip - Google Drive

Can anyone tell me how to clean up the raw data to reduce the file size.

Thank you.

[JJMack · Accepted solution]

Right click and save as the following http://www.mouseprints.net/old/dpr/DeleteAncestorsData.jsx

you can read this thread to learn the reason Re: Different File Sizes SAME HUGE RESULTS