The Flag My Picture app lets you flagify your image by overlaying your images with country flags. There are 196 flags to choose from. The following flags are available:

Afghanistan (AF)
Albania (AL)
Algeria (DZ)
Andorra (AD)
Angola (AO)
Antigua and Barbuda (AG)
Argentina (AR)
Armenia (AM)
Australia (AU)
Austria (AT)
Azerbaijan (AZ)
Bahamas (BS)
Bahrain (BH)
Bangladesh (BD)
Barbados (BB)
Belarus (BY)
Belgium (BE)
Belize (BZ)
Benin (BJ)
Bhutan (BT)
Bolivia (BO)
Bosnia and Herzegovina (BA)
Botswana (BW)
Brazil (BR)
Brunei (BN)
Bulgaria (BG)
Burkina Faso (BF)
Burundi (BI)
Cambodia (KH)
Cameroon (CM)
Canada (CA)
Cape Verde (CV)
Central African Republic (CF)
Chad (TD)
Chile (CL)
China (CN)
Colombia (CO)
Comoros (KM)
Costa Rica (CR)
Croatia (HR)
Cuba (CU)
Cyprus (CY)
Czech Republic (CZ)
Democratic Republic of the Congo (CD)
Denmark (DK)
Djibouti (DJ)
Dominica (DM)
Dominican Republic (DO)
East Timor (TL)
Ecuador (EC)
Egypt (EG)
El Salvador (SV)
Equatorial Guinea (GQ)
Eritrea (ER)
Estonia (EE)
Ethiopia (ET)
Fiji (FJ)
Finland (FI)
France (FR)
Gabon (GA)
Gambia (GM)
Georgia (GE)
Germany (DE)
Ghana (GH)
Greece (GR)
Grenada (GD)
Guatemala (GT)
Guinea (GN)
Guinea-Bissau (GW)
Guyana (GY)
Haiti (HT)
Honduras (HN)
Hungary (HU)
Iceland (IS)
India (IN)
Indonesia (ID)
Iran (IR)
Iraq (IQ)
Ireland (IE)
Israel (IL)
Italy (IT)
Ivory Coast (CI)
Jamaica (JM)
Japan (JP)
Jordan (JO)
Kazakhstan (KZ)
Kenya (KE)
Kiribati (KI)
Kuwait (KW)
Kyrgyzstan (KG)
Laos (LA)
Latvia (LV)
Lebanon (LB)
Lesotho (LS)
Liberia (LR)
Libya (LY)
Liechtenstein (LI)
Lithuania (LT)
Luxembourg (LU)
Macedonia (MK)
Madagascar (MG)
Malawi (MW)
Malaysia (MY)
Maldives (MV)
Mali (ML)
Malta (MT)
Marshall Islands (MH)
Mauritania (MR)
Mauritius (MU)
Mexico (MX)
Micronesia (FM)
Moldova (MD)
Monaco (MC)
Mongolia (MN)
Montenegro (ME)
Morocco (MA)
Mozambique (MZ)
Myanmar (MM)
Namibia (NA)
Nauru (NR)
Nepal (NP)
Netherlands (NL)
New Zealand (NZ)
Nicaragua (NI)
Niger (NE)
Nigeria (NG)
North Korea (KP)
Norway (NO)
Oman (OM)
Pakistan (PK)
Palau (PW)
Panama (PA)
Papua New Guinea (PG)
Paraguay (PY)
Peru (PE)
Philippines (PH)
Poland (PL)
Portugal (PT)
Puerto Rico (PR)
Qatar (QA)
Republic of the Congo (CG)
Romania (RO)
Russia (RU)
Rwanda (RW)
Saint Kitts and Nevis (KN)
Saint Lucia (LC)
Saint Vincent and the Grenadines (VC)
Samoa (WS)
San Marino (SM)
Sao Tome and Principe (ST)
Saudi Arabia (SA)
Senegal (SN)
Serbia (RS)
Seychelles (SC)
Sierra Leone (SL)
Singapore (SG)
Slovakia (SK)
Slovenia (SI)
Solomon Islands (SB)
Somalia (SO)
South Africa (ZA)
South Korea (KR)
Spain (ES)
Sri Lanka (LK)
Sudan (SD)
Suriname (SR)
Swaziland (SZ)
Sweden (SE)
Switzerland (CH)
Syria (SY)
Taiwan (TW)
Tajikistan (TJ)
Tanzania (TZ)
Thailand (TH)
Togo (TG)
Tonga (TO)
Trinidad and Tobago (TT)
Tunisia (TN)
Turkey (TR)
Turkmenistan (TM)
Tuvalu (TV)
Uganda (UG)
Ukraine (UA)
United Arab Emirates (AE)
United Kingdom (GB)
United States (US)
Uruguay (UY)
Uzbekistan (UZ)
Vanuatu (VU)
Vatican (VA)
Venezuela (VE)
Vietnam (VN)
Western Sahara (EH)
Yemen (YE)
Zambia (ZM)
Zimbabwe (ZW)

Step 1:

To overlay your image with a flag, simply tap the "Select a Picture" button and choose a file that is in .jpg, .png or .gif format.

Step 2:

After selecting your image, select a flag from the select menu.

(Optional) You can set the opacity level. The opacity level is set at 30% by default. A higher opacity level means that the flag will become darker. However, if the opacity is set too high, the image that the flag lays over might not be visible enough. For this reason you may want to experiment with the opacity level to find out what works best.

Step 3:

Click the "Overlay Picture" button.

After your picture has been overlaid, you can download it and if you'd like, you can upload it to Facebook, Twitter, Google+, VK or any other social network, forum or site and set the picture as a profile picture, cover photo etc.