Way #2: How to enlarge an image using Photoshop?
Photoshop is an advanced image editor with dozens of sophisticated tools – one of them being image enlargement with different types of resampling options.
We'll learn about this in the section below!
Open Image Size options
From the Image option in the menu bar, select Image Size. A dialog box will open where you can enter the new pixels or resolutions you need for the image.
If you are going to print the photo, you can also adjust the Document Size.
Select the resampling mode
Resampling mode refers to how Photoshop creates new pixels to enlarge your image.
The Bicubic* option is great for enlarging photos where you want to make everything sharper. Photoshop will calculate the average of many pixels and create new ones.
If your photo has a lot of noise and you want to make everything smooth, select the Bicubic Smoother option.
Click OK
That's it! Click on the OK button to save your photo.
* Bicubic interpolation is an extension of cubic spline interpolation (a method of applying cubic interpolation to a data set) for interpolating data points on a two-dimensional regular grid. The interpolated surface (meaning the kernel shape, not the image) is smoother than corresponding surfaces obtained by bilinear interpolation or nearest-neighbor interpolation. Bicubic interpolation can be accomplished using either Lagrange polynomials, cubic splines, or cubic convolution algorithm.