Transparency will not solve the readability of your text if you want the image quality or look to stay the same. If you make the image transparent then the background color will show up by that amount it is transparent. So it will never truly be transparent if your website has a background color which is dark. That is why you need to just make the background white. This will however make the picture simply more white. If that's not what you want then you need to edit the TEXT in the top layer in order to make it more visible.