CONVERT IMAGE FORMAT WITHOUT ANY INTERNET AND SOFTWARE
STEPS:
1. click on start menu
2. search for cmd.exe
3. copy the image that you want to convert on desktop.
4. now name that image as (im)
5. check it's format by going into it's properties.
6. write this command in command prompt :
cd desktop
copy /b im.(original format) "fi.(final format)"
for example : if i have a image name as im and it's format is png. i wants to convert it into ico format, then i has to write this command in command prompt :
cd desktop
copy/b im.png "fi.ico"
it's over, command prompt will change it's format into specified format and save the file on desktop.
HAPPY CODING
if you have any confusion , write it in comment !!