You may use Comment field or info :
Info
If a piece of external information, such as a text file, a picture or a video is to be linked to a field value, this is done in a table that is loaded using an info prefix. (In some cases it will be preferable to store the information inside the .qvw file, by using the Bundle prefix.) The table must contain two columns only, the first one with the field values that will form the keys to the information, the second one containing the information elements, e.g. the file names of the pictures etcetera.
The same applies to, for example, a picture from a database management system. On a binary field, a blob, the info select statement makes an implicit bundle, i.e. the binary data will be fetched immediately and stored in the qvw. The binary data must be the second field in a select statement.
The syntax is:
info ( loadstatement | selectstatement )
Examples:
Info LOAD * FROM flagoecd.csv;
Info SQL SELECT * FROM infotable;
Info SQL SELECT Key, Picture FROM infotable;
