Import Image and export as Txt

Hi, 

I like to create a form where I can import an image and text by a user and export those inputs in txt file. 

For the image import i'm currently using the "event.target.buttonImportIcon()" in JS and for the export to a txt-file I use JS to write the user input into a variable which is saved in the text file. 

Is it possbile to process the imported image in any way? I thought of exporting it as a base64 text for example. Where and how is the image saved when using "buttonImportIcon()") I tried "var photo = (event.target.buttonImportIcon());" and exporting 'photo' but the output is just "0. 

Thanks for any help in advance!