Can anyone say how can I improve the resolution of the images and tables placed in the figures to the journal requirement while there are no chances of taking the subsequent photographs and graphs?
It sounds like you need interpolation software using algorithms to estimate the missing pixels in an image and fill them in, which can help to increase the resolution. Popular options would be Adobe Photoshop and GIMP which allow you to resize and resample images, which can help to improve their quality. Last time I tried it, GIMP was free.
Preprint The improbability of atheism: How the consequences of being ...