1. A computerized method for displaying a modified icon image, comprising: modifying an icon image with a processor performing (A) and (B): (A) retrieving a first original icon image of an operating system associated with applications and files; combining the first original icon image with sub-images as overlays thereon according to a scheme of priorities assigned to the sub-images reflected by relative sizes of the sub-images, such that a first sub-image having a higher priority with respect to a second sub-image is rendered over the first original icon image as a larger sub-image, so as to form a first combined icon image; and replacing the first original icon image with the first combined icon image; displaying the first combined icon image; and (B) registering a dynamic link library (DLL) in a Windows registry with an implementation of an IExtractIcon interface; upon assessing from the file extension that no overlay image for a second original icon image is required, executing an IExtractIon.GetIconLocation function associated with the IExtractIcon interface returning a file path with a file extension thereof of the second original icon image; upon assessing from the file extension that an overlay image for the second original icon image is required, overriding an IExtractIcon.GetIconLocation function associated with the IExtractIcon interface returning a file path with a file extension thereof of the second original icon image comprising: deciding which overlay image to apply to the second original icon image based on the file extension; fetching the second original icon image with a plurality of sizes associated with the file extension; converting the second original icon image to bitmap (BMP) format; reading the decided overlay image in BMP format with a respective plurality of sizes; combining the second original icon image for each of the plurality of sizes with the decided overlay image with the respective plurality of sizes into a second combined icon image; and saving the second combined icon image and returning a second file path to the second combined icon image; and displaying the second combined icon image.