How can I reduce image file sizes for online visa extension submission in Thailand?

The user seeks advice on how to reduce image sizes from Dropbox for a visa extension application, as all their pictures exceed 1MB. Multiple comments offer solutions, including using apps like Paint, online converters, or specific websites like picresize.com. Suggestions to scan documents or convert them to PDFs are also provided, along with methods to achieve smaller file sizes through emailing or using various apps. Some commenters note that regardless of the online submission, a visit to the immigration office is still necessary.