SQLite Android help me with understaning please

Hi guys please forgive me for my english, I am working as a volunteer(I am newbie) in small project and I have one task to do, It is about SQLite database in android and i feel pretty lost :( Basically i had to download file(image) save it to a folder, and if size of desination folder is above 50MB then i have to keep deleting lastmodifed files(from that folder ofc) until 'size of the destination folder' will be again < 50MB. It was pretty simple every single function works pretty good, but now I have to correct my code, and instead of saving date to a folder i have to put it into SQLite Database. Have you got any ideas how to do this, i think i dont understand Databases idea very well ;/ By storing files into SQLite database do I put real files into database file?(in that case images from URL), or do I store only information about stored file(like date of last modification).

Please help if You can.

Here it is simple download method which I am using,

public static byte[] download(Context context, String adress) {
        byte[] image = new byte[2048];
        //Downloading an image

        if (Patterns.WEB_URL.matcher(adress.toString().trim()).matches()) {

            try {
                urlad = new URL(adress.trim());
                filename = Uri.parse(adress.toString()).getLastPathSegment();
                outputFile = new File(filePathFolder, filename);
                InputStream is = urlad.openStream();

                OutputStream os = new FileOutputStream(outputFile);

                int ImageLength;

                while ((ImageLength = is.read(image)) != -1) {
                    os.write(image, 0, ImageLength);
                }



                is.close();
                os.close();

            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } catch (Exception e) {
                e.printStackTrace();
            }
        } else {
            Toast.makeText(context.getApplicationContext(), "Please insert valid url adress", Toast.LENGTH_SHORT).show();
        }

        return image;
    }