How safari on iPad decide size when autoresizing

[balmydrizzle]

If you connect to this url: http://www.celebritywallpaperbase.com/category/1920-x-1440/ & click Drew Barrymore smile & Debby Ryan, respectively. you'll see their size displayed on top of Safari are different. The actually image is 1920x1440. However, Debby's size is correct but Drew's size is shrinked. How does Safari decide the dize when autoresizing?

Is it possible to disable this autoresizing feature cause I want Safari show original clear image when I enlarge the image.

 

[saving107]

As far as your question goes, I don't believe their is any way to turn off autoresizing in safari, but I looked at both from my iPad and saved them to my photos, then I transfered them to my iPhoto library and they both show that are being saved in the correct resolution.

 

[balmydrizzle]

Yes, they are actually both 1920x1440 image file. But I'm confused why Safari show Drew's wallpaper as 960x720? Can you figure out why? I download both image file to my Windows PC and use XnView to see their image information, the only difference seems Drew's has JPEG Truecolor v1.0, whereas Debby's is v1.2. Do you know what this mean?

EDIT: I just find that if I load the image into Photshop & save it as another file(and it has JPEG TrueColor v1.2 now). Safari will display the actual size 1920x1440. But I have another image file with JPEG TrueColor 1.2 format but Safari won't display actual size. So, I am really curious what information does Photoshop write into the output file that makes Safari display actual size on its browser. If anyone know or solve this 'puzzle' please let me know or post here. Thanks!