First you should gather information about the idea as to what type of files you can upload on blogger. You can get information from many sources. You can ask experienced bloggers about their experiences. These bloggers are experienced in their fields and know all kinds of ways which will certainly help you upload files on blogger. People who are professional writers also know about all these types of things as they work for many companies and their blogs.
Type of files
You should also know about the types of files you want to upload on blogger. Files for example GIF, JPG, PNG or BMP formats can easily be uploaded on blogger. Sometimes heavy files might give you some kind of difficulty but usually all types of files can be uploaded on blogger.
Uploading from external server
Uploading from an external server can be tricky sometimes but if you have access to the FTP for your own website, then it relatively easy to upload from that server. Many web developers also appreciate that you should use your own FTP access.
Externally Hosted File
You can also upload externally hosted files as well. It will take a few minutes to upload but still it is another safe method.
By converting a particular file to another file type can also be used when uploading on blogger. Non-compatible files can be converted into another format and blogger will accept it as well.