I have looked at your screenshots, and it seems that your monitor's resolution is 1920 x 1080, so this is not a HiDpi monitor issue.
Also, Photoshop is displaying the image correctly at 150 x 300 pixels, but Chrome seems to have scaled the image up to 150% - 225 x 450 pixels.
If you are certain that Chrome is set to 100% zoom, it's possible is that the Tinypic website is scaling the image to 150%.
Another possibility is that you inadvertently scaled the image before uploading.
You can post the actual image here if you like, it's easy to check the pixel dimensions.
I understand that the dimensions say 150x300 but they aren't the same size visually. I've taken a screenshot of the image in photoshop at 100% beside the image in chrome at 100%. I don't think it's the browser as I've always used chrome and never had this issue, it only started a few days ago, I've also just tried it in firefox and it's exactly the same
I see that your interface looks quite large, so I think the problem is caused by your Windows display settings.
If set to 125 or 150%, it will cause everything to scale up, but Photoshop will still display images accurately.
Go to Control Panel > Display settings (or whatever it's called on Windows 10), and set it to 100%, and the problem should go away.
That does resolve the issue but I've always had the interface a bit larger since I've had the laptop so I wonder why it just seems to have started doing it. Unfortunately everything is tiny on this screen at 100%
You can control the size of the interface in Photoshop under Edit > Preferences > Interface, but the options are only 100%, which you probably find too small, and 200%, which you may find too big.
There is also a setting for UI font size, which only affects the panels.
Chrome also has a setting for text size, under advanced settings.
And remember, Photoshop will always show you the true image size (at 100% view).
You also should check windows scale for monitor. It looks like that screenshot. If you have 125% as recomened in laptops all software will show images biger than it is. Exept photoshop thant shows 100% correct size.
Try to change Display scale in WIndows preferances to 100% and compare.