I have Nexus 7 tablet and got an idea to use it for uploading images into social media. I searched some information to find out how. Somewhat all the needed information was given at Google play store on page for Nexus Media Importer: https://play.google.com/store/apps/details?id=com.homeysoft.nexususb.importer
All I had to do is buy a short OTG cable, an USB card reader and this Nexus Media Importer software. Altogether I paid something like 25 euros for that gear. Now I can import images from SD cards used on my cameras to Nexus 7, and then edit and post them to Internet.
Then abroad I can buy prepaid SIM card for 20 euros with 500MB data limit, which should be enough, because according Nexus 7 my monthly data traffic is sometwhere around 200MB. This will be even less when I force Nexus 7 to update software only when connected via WiFi.