Several points:
People suggest to
compress images. Incorrect terminology, all common image file formats like JPG and PNG are already compressed to near maximum possible data compression. What you need to do is
scale the image to a lower pixel XY size, resulting in smaller file size.
A good freeware tool for image manipulation is Irfanview, from
http://www.irfanview.com/Portable Apps version here:
http://portableapps.com/apps/graphics_pictures/irfanview_portableTo change image size in Irfanview, use menu Image --> Resize/resample --> Set new size (and tick 'preserve aspect ratio')
Then File --> SaveAs and select format (JPG 85% typically, or PNG if you want non-lossy)
For pictures to upload to eevblog I usually set the size to 1000h x (whatever), resulting in filesize less than 200KB.
Regarding whether to use external image fileshare servers, or eevblog upload, the latter is highly preferable because it creates a lasting association between the image and the thread where you posted it. External fileshares can go down or change their URL structure, then the thread has a missing image. But if it's on eevblog server the thread's images will be preserved as long as the thread.
Also, some image servers end up on blacklists, whether local or net-global. For instance in adding some URLs to my usual browser's block lists, I seem to have killed some that people use for images, so those pics don't show up in eevblog for me. I still haven't figured out which entries caused that. This is just one small, laughable example of typical problems with external image servers.
For adding multiple eevblog-served images as full size embeds in a thread... it's not a great idea unless you _really_ want to show off the pics. Since it means the eevblog server expend that bandwidth (operating cost) every time someone fetches that page. Even if they would not have bothered expanding those image thumbnails. So, use sparingly.
But if you must... the easiest way is to type in the text, select the pics to upload as attachments, and send. Then open another browser window to the same post, and click Modify on your post. With the first window, click all the pic attachments so they are full-sized. Now you can right-click on the images in that window to get the URLs for the full-size images, then past the URLs into their places in the text open for editing in the other window. Select each URL and click the 'image' icon (bottom left one in the eevblog post editing tools) to wrap it in the correct codes.