I am having an image whose bit depth is 32 bit. So it is possible to create bit depth higher than 24. But is it possible to have image with more than 32 bit depth like 40 or 48 bit depth. Following wiki link say image more than 24 bit depth possible pls tell me is it possible and how can i achieve it? https://en.wikipedia.org/wiki/Color_depth
Yes you can. Stan comented the basics but I am explaining more.
The base idea is that you have one or several channels.
One channel can be for one color, for example Red, Green and Blue, and you can have yet another channel for transparency. (RGB=3 Channels) (RGBA=4Channels)
On a CMYK file you can have 4 base channels and then one aditional so you can have 5 channels.
Bits on each channel
The second aspect is how many diferent values you can have on each one.
The most used is 8 bits, that can have 256 levels for each channel so you can have 8x3=24, or 8x4=32.
But there are other deep, for example Photoshop can use 16 bits on each channel, so you can have a 16x3=48 bit file, plus another 16 for transparencies and so on.
On Photoshop just go to Mode and choose 16 bits.
Diferent file formats and devices
But other devices uses diferent bith depth than 8 or 16, for example a RAW file from a camera can have 10, 12, 14 bit deepth on each RGB channel.
There is another file type that do not uses bit depth but a floating point, wich are the HDR files. The High dynamic range images. In theory they have more than 16 bits (which are 65k colors) and in theory can have like 24 bit colors on each channel which are arround 24 millions but does not record them as such.
Edited based on your comment:
User can upload any image...
I think it would be better if you limit yourself to some file formats and some bit depths.
It took YEARS for the browsers to accept 32 bit jpg, because they were CMYK files and inclusive today many aplications display CMYK files WRONG!
This is due CMYK files need conversions based on the embeded color profiles, that involve some matrix calculations, etc.
My recomendation is that you Limit your app to:
JPG with RGB information. 24 bits. Remember you can have diferent extensions for the same JPG file.
PNG. Here you can have a 8 bit image, 24 bit image and transparency. You need to know what are you displaying below this transparent space... a white screen? Black one? a choosable background?
Focus instead of displaying the colors right and resample it accordingly to your device.
Expression of Colour Depth in bits
It's probably an image with 8-bit colour-depth over 4 channels. You would have a 32-bit deep CMYK image with each of the inks, C,M,Y, and K having an 8-bit colour-depth.
4 channels (CMYK) x 8-bit colour-depth = a 32-bit colour-depth image
A 24-bit colour-depth would be an 8-bit colour-depth X the three R,G,B image channels.
3 channels (RGB) x 8-bit colour-depth = a 24-bit colour-depth image
We can get-away with this because as we "mix" the channels we get discreetly different hues.