Short Answer: There Is No International Legal Standard
The question of whether a scanned copy of a document is acceptable evidence in a court proceeding or bureaucratic procedure depends upon the rules and laws of each particular country and private organization that requires you to produce records. There is no international regulation that applies across the board, and the rules aren't even necessarily the same for every litigation forum in a country.
In some contexts, acceptance of digitized records is widespread. Acceptance of digitized records tends to be less great in jurisdictions where computers are not a ubiquitous part of life (e.g. Third World and developing country bueaucracies and courts), and tends to be less in bureaucracities than in legal proceedings (because low level bureaucrats are often more rigid than the senior civil servants of the judiciary).
Best Practices For Digitizing Records
The International Standards Organization (ISO), whose standards are often adopted by reference by big businesses, has standard procedures for digitizing records, but these are merely best practices adopted by a reputatable international organization and often incorporated by reference by others, rather than having any legal fource of their own. For example, the U.S. federal government references this standards in connectins with its own E-Gov initiative to digitize its records.
Another set of best practices for digitizing records has been developed by ARMA International (formerly an acronym for the Association of Records Managers and Administrators and now a proper name).
Wikipedia identifies these best practice standards and some select national safe harbor regulations such as those designed by the National Archives in the U.K.
Evolving Standards For Courts
Increasingly, courts in the developed world only require an original rather than a scanned image or photocopy, in cases where the authenticity of the original is in doubt (i.e. where there are facts that suggest that it is possible that the original is fake or forged), but this is certainly not universal international practice for all purposes for which you might use a document.
For example, in U.S. federal courts under the federal rules of evidence, which are copied verbatim or in substance by many state courts, the necessity of an original document for use a court evidence is covered mostly by Rules 901-903 (authentication and identification) and by Rules 1001-1008 (contents of writings, recordings and photographs). The most pertinent of these to your question is Rule 1002:
Requirement of the Original
An original writing, recording, or photograph is required in order to
prove its content unless these rules or a federal statute provides
otherwise.
But, while this default rule would seem to put the kibosh on your plan, in fact, the exceptions to it, largely swallow the general rule of Federal Rule of Evidence 1002. For example, Federal Rule of Evidence 1003 states:
Admissibility of Duplicates
A duplicate is admissible to the same extent as the original unless a
genuine question is raised about the original's authenticity or the
circumstances make it unfair to admit the duplicate.
But, even in the U.S., for example, some immigration court judges are in practice very skeptical of duplicates of documents from foreign countries and insist upon originals.
On the other hand, some U.S. federal trial courts and an increasing minority of state courts in the U.S., require all documents using in court except those for which authenticity is in doubt, to be scanned and used in electronic form only.
Courts in some jurisdictions require originals or original certifications of copies from third parties, if they are used in trials, but not if they are referred to in preliminary litigation paperwork.
Arbitration forums tend to be more lax regarding the requirement of original documents than courts.
The Requirements Of Government Agencies And Corporate Bureaucracies
Government agencies (e.g. immigration offices, the Department of Motor Vehicles, licensing agencies) and large corporate bureaucracies (e.g. life insurance companies and brokerages) often insist on documents that are either originals or are copies of the original with an original certification by the agency that created them (even when no official statute or regulation requires that they do so).
For example, many businesses will not reimburse employees for expenses if original receipts are not provided.
Rules of Thumb
As a rule of thumb, either an original or an original certication of a copy of educational transcripts, birth certificates, death certificates, transcripts of court proceedings, certificates of good standing for a business, and government licenses are often required by government bureaucracies, business bureaucracies, and courts.
It is also a good rule of thumb to keep an original, or a copy of the original with an original certification by a government agency, is necessary for any document that must be signed or that has an official seal.
The need for an original also depends upon substantive law that applies to a particular kind of document. Some documents (sometimes called "real" documents) embody a legal right rather than merely serving as evidence of a legal right. Some examples of "real" documents include: paper currency; "live" checks, money orders and promissory notes; warehouse receipts; stock certicates; certificates of title (depending upon the document, sometimes and sometimes not); and a last will and testament.
In contrast, digital copies are usually sufficient for invoices, bank statements, receipts, pay slips, etc. that do not contain a signature or official seal (and obviously, that are not paper currency).
A Compromise Solution
When a law office or corporation goes "paperless" the most common procedure is to identify each electronically scanned file with some sort of index number. The index number is incorporated in an index that makes it possible to locate the particular box or better yet, labelled folder within a particular box, in which the paper document is stored. The indexing process usually indexes documents arbitrarily with no effort made to keep documents that relate to each other in the same place. The sole purpose of the index is to make it possible to find the original if necessary.
Once documents are scanned and indexed, the firm then to send all of the actual paper documents either to a company that stores them in a remote warehouse (e.g. this one), basement, garage, shed, or a storage unit rented by the company at a self-storage facility.
This makes the day to day offices of the record owner paper free without actually destroying the original records.
Record Retention Policies
A closely related issue is how long you need to retain a document, something for which law firms and businesses often establish a "records retention policy" that depends mostly upon the relevant statute of limitations and the domestic laws that apply to the company.
These policies and laws in some jurisdictions that create a safe harbor for persons who adopt record retention policies balance the practical need to throw out dated paperwork, the circumstances under which paperwork might be needed in the future, and the often harsh penalties for throwing out paperwork if you know that it might be used as evidence against you in a future lawsuit (which is called spoliation of evidence).
A practice of saving paperwork for one year after the relevant statute of limitations for a lawsuit expires is common, but some kinds of paperwork needs to be retained much longer such as vital statistics records (e.g. birth certificates, marriage certificates and divorce decrees) that can prove citizenship and marital status, documents showing the purchase price of property that may later be sold until it is sold (for tax purposes), documents that prove ownership of property that is still owned, documents that prove final payment of debts, many documents related to a divorce, and many documents related to estate planning.
